task 3.b: en trips priority corridors - preliminary street redesign alternatives

116 NEW MONTGOMERY STREET, SUITE 500 SAN FRANCISCO, CA 94105 415-284-1544 FAX 415-284-1554

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M E M O R A N D U M To: EN TRIPS Technical Advisory Committee

From: EN TRIPS Project Team

Date: July 28, 2011

Subject: South of Market Corridor Project Alternatives

This memorandum provides descriptions and analysis of the concept alternatives that the EN TRIPS project team has developed for the EN TRIPS corridor projects in the South of Market area: Folsom and Howard Streets between 5th and 11th Streets; Seventh and Eighth Streets between Market and Harrison Streets. The project team considered a total of ten alternatives. Of these ten, the alternatives selected for further development following preliminary screening are described in detail below. All ten alternatives are detailed in Appendix 1.

Introduction

The study team approached this pair of South of Market one-way couplets with the understanding that the streets share a number of similarities, but that each also has specific challenges and opportunities of its own, related to each street’s particular land uses and role in the circulation network.

The streets are similar in important ways: they are a pair of one-way couplets, with Folsom/Howard providing east-way travel through the South of Market, and Seventh/Eighth streets providing north-south travel. All four streets have identical rights-of-way (82.5 feet), Muni bus service at moderate frequency, one-way bicycle lanes, four one-way travel lanes serving high volumes of vehicle traffic, and on-street parking on both sides. Figure 1 shows the existing cross-section for Folsom, Seventh and Eighth Streets. Please note that on Howard, sidewalks are 12 feet wide and remaining elements are slightly narrower.

Figure 1 Existing Cross-Section: Folsom, Seventh and Eighth1

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1 For all Folsom, Howard, Seventh and Eighth Streets cross-sections, please note that for simplicity’s sake,

total widths are shown as 82 feet (actual rights-of-way are 82’-6”). As these are concept alternatives, all dimensions should be viewed as approximate and subject to refinement.

Nelson\Nygaard Consulting Associates Inc. •

Common Design Principles for South of Market Arterials

Because of these similarities, the project team developed a common initial list of concept alternatives for all four streets. Key shared design principles are described below.

Pedestrian comfort and safety should be improved. Pedestrian challenges are widespread throughout the South of Market arterial network. Particularly in areas where pedestrian volumes are likely grow, corridor projects should seek to improve comfort for pedestrians while reducing the risk of collisions. Projects should seek to:

Increase pedestrian and public open space: Increase pedestrian space should be provided by providing wider sidewalks (achieving Better Streets Plan minimum or, preferably, recommended standards) and bulb-outs.

Moderate vehicle speeds: Vehicle speeds should be moderated through road diets or other traffic calming measures so that conditions are more comfortable for pedestrians, and the risk of pedestrian collisions is lower.

Improve pedestrian comfort with amenities such as landscaping and pedestrian-scale lighting.

Maintain or improve “buffers” from traffic.

Pedestrian connectivity should be improved. Long blocks without signalized mid-block crossings restrict pedestrian connectivity throughout the South of Market, and long crossing distances can make crossing the street difficult for some pedestrians, vehicle volumes are high. Projects should seek to:

Improve pedestrian connectivity with the addition of mid-block crosswalks, particularly at alleys

Reduce pedestrian crossing distances by widening sidewalks and/or providing pedestrian refuges.

Bicycling should be made safer, more comfortable and attractive. All four segments are key links in the South of Market bicycle network, currently featuring Class II bicycle lanes. Given this role, a high priority should be placed on maintaining the existing bicycle quality of service on these corridors. As vehicle volumes and demand for cycling may increase over time, it might also be appropriate to develop protected facilities, or consolidate directions of travel.

Transit speed, reliability, access and legibility should be improved. While none of the segments lie along the highest-frequency Muni corridors, increased transit service is planned as part of the Transit Effectiveness Project. In some cases, transit priority treatments may be appropriate. Due to the streets’ one-way configurations, bus routes using these segments are currently divided by direction of travel – consolidation of both directions of travel would improve transit legibility.

Maintain adequate vehicle capacity in the South of Market network as a whole. Projects should seek to maintain enough vehicle capacity in the network as a whole so that existing South of Market vehicle volumes can continue to be accommodated with undue increases in delay for drivers and transit riders. Projects will not necessarily seek to accommodate the vehicle volumes forecast for the project horizon year. The goal of maintaining vehicle capacity will be balanced against priorities for the public realm and other modes of transportation.

Delivery access to businesses should be maintained or improved. A number of street-fronting retail businesses taking loading from the sidewalk exist along all four segments.


To maintain economic vitality, it is essential that a reasonable degree of access to these businesses for delivery vehicles be maintained.

Open space, landscaping and other urban design elements should be enhanced. Existing designs and amenities of all four segments are inadequate in terms of fostering an attractive and healthy public sphere. In particular, relatively narrow sidewalks (generally 10 feet) provide little opportunity for additional landscaping elements.

Capital cost and implementation timeline should be considered minimized. Given limited resources, cost and implementation timeframe should be taken into account in comparing project alternatives.

In many cases, these priorities will compete for space in a limited right-of-way. Not all goals can be met fully on all streets. Evaluation criteria have been developed reflecting these design principles.

Alternatives Developed for South of Market Arterials

The project team considered a total of ten alternatives. The complete list of alternatives is summarized in Figure 2, and details of each are provided in Appendix 1.The alternatives selected for further development following preliminary screening are described in detail in the sections that follow.

Figure 2 Folsom, Howard, Seventh & Eighth: All Alternatives

Alternative Description Possible Applications

1 1-Way: 2 Lanes + Buffered Bike Lane F/H & 7/8

2 1-Way: 2 Lanes + Buffered Bike Lane + Busway 7/8

3 1-Way: 3 Lanes + Buffered Bike Lane F/H & 7/8

4 1-Way: 3 Lanes + Bike Lane F/H & 7/8

5 1-Way/2-Way: 2 Lanes one way + Buffered Contraflow Lane (Folsom), 2 Lanes one way + Cycletrack (Howard)

F/H

6 1-Way/2-Way: 2 Lanes one way + 1 Lane other (Folsom), 2 Lanes one way + Cycletrack (Howard)

F/H

7 2-Way: 1 Lane each way + Center Turn Lane F/H & 7/8

8 2-Way: 1 Lane each way + Buffered Bike Lanes (Folsom), 2 Lanes each way (Howard)

F/H

9 2-Way: 2 Lanes one way, 1 Lane other + Buffered Bike Lane F/H

10 2-Way: 1 Lane + 1 Peak Towaway Lane each way + Cycletrack F/H


Folsom and Howard Streets2

Folsom/Howard Major Issues and Opportunities

Major issues and opportunities specific to Folsom and Howard Streets include:

Neighborhood Connectivity. Working together in a one-way couplet Folsom and Howard Streets travel through the center of the western and eastern South of Market neighborhoods, connecting them to the Transbay District and downtown. Unlike Seventh and Eighth Streets, Folsom and Howard have no freeway ramps, so they offer more flexibility for design changes.

Forecast growth. Folsom and Howard Streets are projected to see substantial growth in residential and employment density as a result of recently completed land use planning efforts. The forecast growth suggests that overall pedestrian volumes could be expected to rise, particularly on Folsom Street.

Substandard pedestrian facilities. Pedestrian facility deficiencies on both streets include narrow sidewalks, long crossing distances, and long distances between crossings. To the west of Fifth, Folsom Street’s 10-foot sidewalks do not conform to the Better Streets Plan standard of 12 feet for Mixed Use streets. Folsom also has relatively high pedestrian injury collision rates of 25 and 32 per mile east and west of Fifth over the period between 2004 and 2008.

Bicycle priority: Folsom and Howard Streets provide a vital east-west link in the South of Market bicycle network in a part of the City that is expected to see substantial growth in vehicle traffic. As an important street for bicycles, Folsom and Howard are projected to have relatively high vehicle traffic volumes. They have also suffered in the past from relatively high rates of bicycle collisions.

Community Priority. Folsom Street was also identified as a high-need corridor in the Eastern Neighborhoods area plans, and improving Folsom was specified as a priority project by the San Francisco Board of Supervisors. The Western SOMA Community plan identifies SOMA as a center of that community and key pedestrian and transit travel corridor, focusing on the western segment of Folsom between Fourth and Eleventh Streets.

Folsom/Howard Alternatives Considered but Rejected

Following is a brief summary of reasons for rejection of the remaining alternatives:

Alternatives 2, 3 and 4 each feature three lanes, one-way. While Alternatives 3 and 4 have been recommended for further consideration on Seventh and Eighth Streets, where traffic demands are greater, these alternatives were deemed to provide insufficient traffic calming and other benefits for Folsom and Howard.

Alternative 5 is similar to Alternative 6; however, its buffered transit/travel lane configuration would likely result in pedestrians crossing the lane outside of crosswalks mid-block, a potentially unsafe condition, and one that could significantly slow buses operating in that lane.

Alternative 7 would have significant impacts on traffic while not providing significant benefits for pedestrians, cyclists or transit.

2 While Folsom Street was identified at the key corridor of concern for the community, and will be the primary focus of

this design effort, Howard has been included in the Alternatives Analysis because it currently forms a one-way couplet with Folsom Street. Any major circulation change to Folsom will also have to include careful consideration of the role of Howard Street in the network.


Alternative 7 was rejected primarily because it would create significant challenges for transit speed and reliability on Folsom Street. Moreover, traffic on Howard could be expected to increase substantially as the new configuration of Folsom would divert traffic in its direction.

Alternative 10 would essentially leave Folsom a four-lane street, with limited benefits for pedestrians or the public realm.

All alternatives are summarized in Appendix 1.

Folsom/Howard Alternatives Recommended for Further Consideration

For Folsom and Howard Street, Alternatives 1, 6, and 9 have been recommended for further consideration.

Figure 3 Folsom/Howard: Recommended for Further Consideration

Alternative Description

1 1-Way: 2 Lanes + Cycletrack

6 1-Way/2-Way: 2 Lanes one way + 1 Lane other (Folsom), 2 Lanes one way + Cycletrack (Howard)

9 2-Way: 2 Lanes one way, 1 Lane other + Buffered Bike Lanes

Alternative 1 (2 Lanes + Buffered Bike Lane)

Figure 4 Alternative 1 Cross-Section

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This alternative would provide significant benefits for pedestrians, cyclists, and the public domain, with 15-foot sidewalks, wide one-way cycletracks, buffer spaces that could be used for medians and pedestrian refuges at corners, and the traffic calming benefits of a reduction from four to two travel lanes (in order to maintain traffic flow, turn pockets could be provided in the space allotted for parking at other points).

Benefits and Concerns

Maintaining one-way configuration would allow for a number of advantages related to signal timing. Signalized mid-block crosswalks could be provided on each block without causing adverse impacts for transit and vehicle flow. Signals could also be timed to allow for a consistent vehicle travel speeds between 13 and 18 miles per hour, which would be optimal for pedestrian safety and comfort.

The one-way configuration would not allow for consolidation of current or planned transit routes operating in different directions on different streets. Alone among the one-way options for Folsom/Howard, this alternative would feature just two travel lanes, rather than three. This would reduce traffic capacity significantly; however, modeling suggests that a reasonable degree of capacity could be maintained if two through lanes and turn lanes were provided each way.

Reducing the number of through lanes to two would allow for significant improvements for pedestrians, cyclists and the public realm, including 15-foot sidewalks, greatly reduced crossing distances, generous buffered bike lanes and space for limited medians at crosswalks. Even in a one-way configuration, there could also be significant traffic calming.


Maintaining the existing one-way configuration, meanwhile, would allow for crosswalks to be provided mid-block – a matter of particular importance on Folsom and Howard, where blocks are especially long (roughly 900 feet). Mid-block crosswalks could be provided in two-way alternatives, but in order to time signals and maintain acceptable traffic flow (and speed and reliability for any transit vehicles operating on the street), lights would have to be timed in at least one direction, resulting in significant delay in the opposite direction.

Figure 5 Alternative 1 Summary Evaluation

Mode/Category Rating Comments

Pedestrian ++ Major sidewalk widening, reduction in crossing distance; mid-block crosswalks, ped refuges possible

Transit / Waiting environment more pleasant along traffic-calmed street; buses would be slightly slower during peak periods than existing

Bike ++ Wide buffered bike lanes; lane on Howard would provide suboptimal network connectivity

Auto Travel

-

Capacity reduced, although two through lanes could be maintained each way, and turn pockets provided

Parking/Loading / A few spaces would have to be removed to provide mid-block crosswalks and safe sightlines for buffered bike lane

Urban Design + Significantly wider sidewalks; maximum width of roadway reduced significantly; opportunities to provide limited median space at crosswalks (using buffer)

Cost/ Constructability --

Relocation of curb lines, potential medians

++ Major benefit + Minor benefit / No change - Minor impact -- Major impact


Alternative 6 (2 Lanes one way + 1 Lane other on Folsom, 2 Lanes one way + Cycletrack on Howard)

Figure 6 Alternative 6 Cross-Section (Folsom)

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Figure 7 Alternative 6 Cross-Section (Howard)

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This alternative would provide two eastbound travel lanes and one westbound travel lane on Folsom Street. It would provide two westbound travel lanes and a two-way cycletrack on Howard.

Two-way travel on Folsom Street would allow for transit service to be consolidated; however, in order to allow for mid-block crosswalks, signals would have to be timed to favor the primary (two-lane) direction of travel.


This alternative would allow for very wide sidewalks – 16 feet – on Folsom. This additional width would also be more complementary to the desired character along Folsom between 6th and 7th Streets.

It would also allow transit service to be consolidated on Folsom, and for a two-way buffered cycletrack to be provided on Howard.

The additional width of the buffer median on Howard allows for ADA access along the parking edge without the extent of potential conflict with the two-way cycletrack.

However, this alternative consolidates all bicycle travel on Howard Street. This is a disadvantage for bikes, because Folsom would provide better connectivity to the Mission District’s two major north-south bicycle routes (Folsom and Valencia).

A 12 foot-wide two-way cycletrack on Howard Street has the potential to be an iconic addition to San Francisco’s streets and bike network and could enhance the places along Howard Street. The cycletrack buffer could be used for small median islands at crosswalks.



Pedestrian ++ Major sidewalk widening on Folsom, some widening on Howard; reduced crossing distance; mid-block crosswalks, ped refuges possible

Transit / Folsom/Harrison service consolidated on Folsom; waiting environment more pleasant along traffic-calmed street; buses would be somewhat slower than existing

Bike + 2-way buffered cycletrack; however, Folsom would provide better network connectivity (to lanes on Folsom in Mission District) than Howard


Auto Travel

-

Capacity reduced, although two through lanes could be maintained each way, and turn pockets provided

Parking/Loading / A few spaces would have to be removed to provide mid-block crosswalks

Urban Design + Potential for 24-foot wide public space/green infrastructure on either side of Folsom at bulb-outs near pedestrian crossings; however, for most of its length, Folsom will have a curb-to-curb distance of 50 feet.




Alternative 9 (2 Lanes one way, 1 Lane other + Buffered Bike Lane)


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This two-way alternative would allow for three lanes of traffic on each street (two in one direction and one in the other), plus buffered bicycle lanes and somewhat wider sidewalks.


Unlike Alternative 8, this alternative makes “complete streets” changes to both Folsom and Howard, including pedestrian improvements.

This alternative would consolidate transit service on Folsom without impacting speed and reliability to the extent of Alternatives 8. In contrast to Alternative 6, which provides a two-way cycletrack on Howard, and Alternative 8, which provides buffered bike lanes in both directions on Folsom, it would provide buffered bike lanes on Folsom and on Howard.

Like Alternative 8, it would provide three travel lanes in each direction, but with capacity split between Folsom and Howard (traffic would be blocked westbound on Folsom by buses stopping in the single travel lane in that direction).



Pedestrian + Some sidewalk widening; reduced crossing distance; mid-block crosswalks, ped refuges possible

Transit + Folsom/Harrison service consolidated on Folsom; island stops westbound help to brand Folsom as east-west SOMA transit spine; waiting environment more pleasant along traffic-calmed street; buses would be somewhat slower than existing

Bike ++ Buffered bike lanes; existing network configuration retained

Auto Travel

-

Existing four-lane, one-way configurations replaced by 2+1 on each street, with space for turn pockets


Parking/Loading / A few spaces would have to be removed to provide mid-block crosswalks

Urban Design + This alternative provides improvements evenly to Folsom and Howard; The 4’ buffer could accommodate trees and a buffer median for ADA.




Summary Comparison of Folsom/Howard Alternatives

Figure 11 Summary Comparison of Folsom/Howard Alternatives

1 6 9

Pedestrian ++ ++ +

Transit / / +

Bike ++ + +

Auto Travel

- - -

Parking/Loading / / /

Urban Design + + +

Cost/ constructability

-- -- --



Seventh and Eighth Streets

Seventh/Eighth Major Issues and Opportunities

Seventh and Eighth Streets from Market to Harrison, which work together to form a one-way couplet through the western South of Market area, were selected for improvement. Major issues include:

Neighborhood Connectivity. Seventh Street travels north and south between its intersection with 16th Street through the South of Market and across Market Street, where it connects to the north of Market street grid. With this alignment, Seventh Street has unique role as a connecting street between several of the Eastern Neighborhoods for drivers, pedestrians, and cyclists.

Forecast growth. Seventh and Eighth Streets cut through the portion of the western South of Market where substantial new development is forecast as the result of recent zoning changes. They also intersect with Market Street in the Mid-Market area, which the City has prioritized for economic development in the coming decades.

Substandard pedestrian facilities. Sidewalks are 10 feet, below the BSP standard of 12 feet for Mixed Use streets. Multiple turn lanes and restricted crossings occur at Seventh and Harrison. Seventh and Eighth Streets have a high pedestrian injury collision rate of 35 over the period between 2004 and 2008.

Bicycle priority. Forecast traffic conditions would degrade conditions for cyclists in the bicycle lanes on Seventh and Eighth Streets, which together make up a key north-south link for cyclists between Potrero Hill and the Civic Center area.

Seventh/Eighth Alternatives Considered but Rejected

Alternates 3 and 4 have been recommended for further consideration for Seventh and Eighth

Streets. Following is a brief summary of reasons for rejection of the remaining alternatives:

Alternatives 1, 2, and 5 through 10 would all significantly reduce vehicle capacity, and Seventh and Eighth have greater existing and projected vehicle demand than Folsom and Howard. While traffic calming is a desirable outcome, a severe reduction in capacity could have significant impacts on transit, auto, pedestrian, cyclist and conditions on surrounding streets, and on transit performance in the Seventh/Eighth corridor. Furthermore, the existing one-way couplet configuration is less problematic on Seventh and Eighth than on Howard, as the existing Muni line using the streets (Line 19) is split by the configuration over only a short distance, and there are no major network connectivity issues associated with the bicycle lanes on both streets.

Seventh/Eighth Alternatives Recommended for Further Consideration

Alternates 3 and 4 have been recommended for further consideration.

Figure 12 Seventh/Eighth: Recommended for Further Consideration


3 3 Lanes + Cycletrack

4 1-Way: 3 Lanes + Bike Lane


Alternative 3 - 3 Lanes + Buffered Bike Lane


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This alternative would provide three northbound vehicle lanes and buffered northbound bicycle lane on Seventh, with the same configuration southbound on Eighth Street. It would provide significant benefits for cyclists and modest benefits for pedestrians and the public domain. Maintaining three lanes would benefit transit and vehicle travel.


Alternatives 3 and 4 are similar: Both would maintain the existing one-way couplet configuration, and three of the existing four travel lanes in each direction. This is because Seventh and Eighth connect to Highway 101 ramps near one end of the segment, at Harrison and Bryant Streets. Alternatives providing just two travel lanes would be severely congested during peak periods, with significant impacts on other users of the street.

Maintaining one-way configuration would allow for a number of advantages related to signal timing. Signalized mid-block crosswalks could be provided on each block without causing adverse impacts for transit and vehicle flow. Signals could also be timed to allow for a consistent vehicle travel speeds between 13 and 18 miles per hour, which would be optimal for pedestrian safety and comfort.

Alternatives 3 and 4 differ in the relative priority they place on pedestrian and bicycle improvements. Alternative 3 would provide a generous buffered bike lane on each street; in order to do so, sidewalks would be widened only modestly, from 10 to 12 feet. However, the three-foot buffer zone adjacent to the parking lane could be used as a (nonstandard) pedestrian refuge by pedestrians, and where a left-turn lane was not necessary, it could be combined with the parking lane to create a roughly 10-foot median island.



Pedestrian + Some sidewalk widening; reduced crossing distance; ped refuges possible

Transit / Little change from existing condition

Bike + Wide buffered bike lanes

Auto Travel / Capacity slightly reduced, but should remain adequate

Parking/Loading / Little change from existing condition

Urban Design + Wider sidewalks, maximum width of roadway reduced significantly by buffered bike lanes configuration; opportunities to provide limited median space at crosswalks

Cost/ Constructability

-- Relocation of curb lines, potential medians



Alternative 4 (3 Lanes + Bike Lane)


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This alternative would also provide three northbound vehicle lanes and buffered northbound bicycle lane on Seventh, with the same configuration southbound on Eighth Street. This alternative provides wider sidewalks than Alternative 3 but does not provide a protected bicycle facility, so the tradeoff is primarily between the cyclist and the pedestrian.


Alternative 4 would differ from Alternative 3 in that it would reallocate space used for a bike lane buffer in Alternative 3 to sidewalks. Sidewalks, then, could be 15 feet wide, compared to 10 feet today. This additional sidewalk space would benefit both pedestrians and the public sphere, as it would provide more space for landscaping and civic amenities. However, unlike in Alternative 3, limited medians could not be provided.



Pedestrian + Major sidewalk widening, reduced crossing distance

Transit / Little change from existing condition

Bike / Little change from existing condition

Auto Travel / Capacity slightly reduced, but should remain adequate

Parking/Loading / Little change from existing condition

Urban Design + Significantly wider sidewalks

Cost/ Constructability

-- Relocation of curb lines


Summary Comparison of Alternatives

Figure 17 Summary Comparison of Seventh/Eighth Alternatives

3 4

Pedestrian + +

Transit / /

Bike + /

Auto Travel / /

Parking/Loading / /

Urban Design + +


Cost/constructability

-- --



Appendix 1. Comparison of Alternatives for all South

of Market Arterials

One-way Alternatives




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This alternative would provide significant benefits for pedestrians, cyclists, and the public domain, with 15-foot sidewalks, wide one-way cycletracks, buffer spaces that could be used for medians and pedestrian refuges at corners, and the traffic calming benefits of a reduction from four to two travel lanes (in order to maintain traffic flow, turn pockets could be provided in the space allotted for parking at other points). Its one-way configuration would also allow for signals to be timed so that mid-block crosswalks could be provided without adversely impacting traffic flow (or transit speed and reliability, as buses would use traffic lanes). However, its one-way configuration would not allow for consolidation of current or planned transit routes operating in different directions on different streets.

This alternative has been carried forward for Folsom Street and Howard Streets, and is discussed in detail above. It has been rejected for Seventh and Eighth Streets because lower capacity would create significant transit delay and vehicle congestion.

Alternative 2 (2 Lanes + Buffered Bike Lane + Busway; Seventh & Eighth Only)


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By providing physically separated transit lanes, this alternative could provide significant speed and reliability benefits for transit, especially during peak periods when freeway-related congestion exists. It would also provide bicycle lanes protected from traffic, although these lanes would be adjacent to bus lanes.

It has been rejected for Seventh and Eighth Streets because lower capacity would create significant vehicle congestion. Because of bus/bike conflicts, the shared bus and bike lane may not provide significant benefits for Muni operations.



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This alternative would provide significant benefits for cyclists and modest benefits for pedestrians and the public domain while having only a limited impact on vehicle and transit operations.

This alternative has been rejected for Folsom and Howard because the two-lane/one-way alternatives better meet the goal of traffic calming and creating a civic boulevard on Folsom Street. It has been carried forward for Seventh and Eighth Streets and is discussed in more detail above.

Alternative 4 (3 Lanes + Bike Lane)


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This alternative provides wider sidewalks than Alternative 3, so the tradeoff is primarily between the cyclist and the pedestrian.

This alternative has been rejected for Folsom and Howard because the two-lane/one-way alternatives better meet the goal of traffic calming and creating a civic boulevard on Folsom Street. It has been carried forward for Seventh and Eighth Streets and is discussed in more detail above.

One-way/Two-way Alternatives

Alternative 5 (2 Lanes one way + Buffered Contraflow Lane on Folsom, 2 Lanes one way + Cycletrack on Howard)


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This alternative would provide two travel lanes in one direction plus a buffered space in the opposite direction that could be used as a “contraflow” transit-only or mixed-flow travel lane on Folsom and as a two-way cycletrack on Howard. Two-way travel would allow for transit service to be consolidated; however, in order to allow for mid-block crosswalks, signals would have to be timed to favor the primary (two-lane) direction of travel. Also, the cycletrack would be on Howard, which does not provide the same degree of network connectivity as Folsom.

This option has been rejected for Folsom and Howard because, with parking outside the contraflow bus lane, all parkers would likely cross through the bus lane, creating a safety hazard and an operational challenge for Muni. It is also not clear that accessible parking could be provided in this scenario. Alternative 6 provides many of the same advantages without these challenges.


Alternative 6 (2 Lanes one way + 1 Lane other on Folsom, 2 Lanes one way + Cycletrack on Howard)



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This alternative would essentially “flip” the buffered transit or travel lane in Alternative 5, allowing for wider sidewalks and making it so that the parking lane was adjacent to the sidewalk, rather than separated from the sidewalk by a lane of moving traffic.

This alternative has been carried forward for Folsom and Howard Streets, and is discussed in more detail above.

Two-way Alternatives

Alternative 7 (1 Lane each way + Center Turn Lane)


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This “Valencia” option (so named because a similar configuration exists on that street north of 15th Street and south of 19th Street) would significantly reduce traffic capacity and significantly calm traffic by reducing through travel to one lane each way (plus a center left-turn lane). It would also allow for bicycle lanes and transit routes to be consolidated on a single street.

This option has been rejected for both Folsom/Howard and Seventh/Eighth because significantly reduced capacity would create delay for transit and vehicles.

Alternative 8 (1 Lane each way + Buffered Bike Lanes on Folsom, 2 Lanes each way on Howard)


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This alternative would also reduce Folsom Street to one through lane each way (turn pockets could potentially be provided in the space allotted to parking), and would provide buffered bike lanes and wider sidewalks. In order to offset the reduction in traffic capacity on one street (Folsom), four lanes of traffic would be maintained on the other (Howard).

This alternative makes explicit and significant trade-offs. In order to maximize traffic calming benefits and allow transit service and bicycle infrastructure to be consolidated on Folsom – the community-defined “main street” of the neighborhood – it would leave Howard more or less “as is”: a four-lane, auto-oriented arterial.

While four lanes of traffic would be maintained on Howard, vehicle capacity on Folsom would be reduced significantly – not just because there would be only one through lane in each direction, but because there would be limited opportunities to provide turn pockets (at 5th and 6th, two-way cross streets, left-turn pockets could be provided, but not right-turn pockets, meaning that through traffic would be blocked by right-turn queues), and because buses would have to stop in the travel lane (bus stops would be located on islands in the parking lane, which in turn would result in some conflicts between cyclists and transit riders crossing the bike lane).

This alternative has been rejected primarily because it would create significant challenges for transit speed and reliability on Folsom Street. Transit vehicles would be delayed by increased congestion. In some cases, they would also have to wait behind vehicles waiting to turn left.

Moreover, traffic on Howard could be expected to increase substantially as the new configuration of Folsom would divert traffic in its direction. With a two-way configuration and significantly more traffic due to diversion from a lower-capacity Folsom Street, Howard Street would be similar in character to the existing configuration of Sixth Street.

Alternative 9 (2 Lanes one way, 1 Lane other + Buffered Bike Lane)


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This two-way alternative would allow for three lanes of traffic on each street (two in one direction and one in the other), plus buffered bicycle lanes and somewhat wider sidewalks. It has been carried forward for Folsom and Howard, and is described in more detail above.

This option has been rejected for Seventh/Eighth because significantly reduced capacity would create delay for transit and vehicles.

Alternative 10 (1 Lane + 1 Peak Towaway Lane each way + Cycletrack)


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This alternative would maintain peak-period traffic capacity using a “tow-away” lane in each direction, in order to provide two lanes each way during peak periods.

On Folsom, it would provide one lane each way plus parking/loading during the off-peak. It would provide a 15’ sidewalk on one side of Folsom street, with a 10’ sidewalk on the other side, and a two-way cycle track separated by a three foot buffer. Howard Street would maintain the existing 12-foot sidewalks, along with bike lanes on both sides of the street. One permanent travel lane and one peak period travel lane/parking lane would be provided in each direction.

This alternative has been eliminated for Folsom and Howard because it offers only limited

improvement in the pedestrian realm for Folsom Street.

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M E M O R A N D U M To: EN TRIPS Technical Advisory Committee

From: EN TRIPS Project Team

Date: July 28, 2011

Subject: 16th Street Corridor Project Alternatives

Introduction

This memorandum provides descriptions and analysis of the conceptual alternatives that have been developed for 16th Street between Potrero Avenue and Seventh Street.

On 16th Street, improvements for transit users have been given the highest priority (Muni has proposed to reroute Line 22, already one of its busiest routes, to serve Mission Bay via 16th). Benefits for pedestrians, cyclists and the public realm are also priorities.

Figures 1-4 show the existing cross-sections for 16th Street, moving from west to east (note that parking lanes are not striped in all locations; in these segments, 8 feet for parking is assumed).

Figure 1 Existing Cross-Section (Potrero to San Bruno)


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Figure 2 Existing Cross-Section (San Bruno to Kansas)


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Figure 3 Existing Cross-Section (Kansas to Wisconsin)

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Figure 4 Existing Cross-Section (Wisconsin to Missouri)

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As the following are concept alternatives, all dimensions should be viewed as approximate and subject to refinement.

It should be noted that all alternatives that do not feature bicycle lanes assume improvements to conditions for cyclists on 17th Street. Potential improvements are described in the section of this memo titled “17th Street Bicycle Corridor.” It should also be noted that all alternatives assume prohibition of left turns from 16th Street, and that in order to maintain auto capacity between Mission Bay and the Mission District, changes to the street network are assumed. These concepts are described under “Grid Repair.”

Major Issues and Opportunities

Because the 22 Fillmore service planned for 16th Street will be a vital transit link between several growing neighborhoods in the EN TRIPS study area, 16th Street will require transit priority treatments on all four of its major segments. As an important first step toward these improvements, 16th Street between Potrero Avenue and Seventh Streets was selected for a corridor project. Detailed on needs for the Sixteenth between Potrero and Seventh Streets are as follows:

Neighborhood Connectivity. Sixteenth Street is the only east-west arterial that extends all the way from the Mission District to the eastern waterfront. As such, it is a vital vehicle and transit connection for three of the Eastern Neighborhoods, and will become even more important as Mission Bay and the waterfront develop.

Forecast growth. Land use densities in this section are currently low. However, due to rezoning as part of the Eastern Neighborhoods land use plan, as many as 3,000 new housing units could be built along this segment of 16th by 2035, leading to a substantial growth in residential density, as well as increasing vehicle and pedestrian travel demand. Additional development is expected in the northern part of the Potrero Hill neighborhood, in Showplace Square, and in Mission Bay, neighborhoods that are linked by the 16th Street corridor.

Transit priority: In 2035, demand for ridership on the 22-Fillmore is forecast to exceed available capacity between Guerrero and Arkansas. While it currently turns off of 16th street at Kansas Street, as routed in the TEP, the 22 Fillmore will run the length of 16th Street, completing the transit connection through the Mission, Showplace Square, and Potrero Hill neighborhoods. The 22 currently suffers from delay and poor reliability, and forecast traffic congestion on 16th (particularly at Potrero Avenue), could further delay this route in its future alignment. At 7th Street, 16th Street passes under I-280 and over the Caltrain tracks. A major concern for 16th Street transit service is the implementation of California High Speed rail in the Caltrain corridor. As discussed in detail in the EN TRIPS future conditions document, some potential alignments of Caltrain and California High Speed rail following full implementation could preclude the extension of the 22-Fillmore service across the Caltrain right-of-way on the surface. City agencies, Caltrain, and the High Speed Rail Authority are currently working together to develop alignment alternatives. Because of this ongoing uncertainty, the eastern extent of the corridor design project will be just to the west of Seventh Street, and the EN TRIPS project will not create designs for the 7th Street intersection or the Caltrain crossing at this time.

Bicycle priority: Bicycle lanes currently exist on 16th between Kansas and Third Streets, and the San Francisco proposes extending bicycle lanes to Terry Francois Boulevard on the east and Potrero Avenue on the west. West of Potrero, bicycle lanes will continue on 17th Street. In the future condition, other modes will compete for this space.

Pedestrian facilities. Through much of this segment, sidewalks are narrow, and the pedestrian environment has few street trees or other amenities. As population densities


increase, the pedestrian environment will have to be upgraded. Most intersections in this segment are unsignalized, leading to difficult crossings for some pedestrians.

Community priority. Sixteenth Street was identified as a high-need corridor in the Eastern Neighborhoods area plans, and improving 16th was specified as a priority project by the San Francisco Board of Supervisors. The segment of Sixteenth Street between the freeways was identified as an area of need by several participants in the EN TRIPS community workshop. EN TRIPS community workshop participants stressed the importance of 16th Street as a transit corridor. In addition, many participants stressed the necessity to improve transit service in the Potrero Hill neighborhood as a whole.

Design Principles

A number of principles were used to develop the design alternatives for 16th Street:

Speed and reliability of future transit services should be ensured. If the 22-Fillmore is to be realigned to serve Mission Bay and if future growth in the corridor is to be accommodated, then protection against projected increases in traffic should be provided for transit service. All alternatives include segments of dedicated lanes. Additional measures to improve speed and reliability are also assumed, including optimzed stop spacing (with stops at 7th, Connecticut, Rhode Island, and Potrero only) and raised platforms enabling level boarding would be provided.

A safe, comfortable and attractive bicycle route should be provided within the corridor. Both 16th and 17th Streets currently feature Class II bicycle lanes. Because the lanes continue east on 16th only, and west on 17th only, lanes on both streets might not be necessary (grades on the streets are similar, and there is less traffic on 17th). If an alternative that did not provide lanes on 16th were to be adopted, however, it is assumed that significant improvements to bicycle facilities on 17th would be made, potentially including a bicycle- and pedestrian-only extension of 17th east into Mission Bay.

The street grid as a whole must continue to accommodate east-west vehicle travel between the Mission District and Mission Bay. As alluded to in the selection criteria, 16th Street is the only east-west through route between South of Market and Cesar Chavez Street. It is therefore of vital importance for all modes. If transit, pedestrian and bicycle conditions are to be improved in a period of growing auto travel, however, alternatives must be developed. Each of the design alternatives is premised on the notion of “grid repair,” or improvements to the connectivity of parallel routes in order to provide alternatives for travel by all modes.

Maintenance of existing curbside parking and loading may be less important in this context. This is primarily due to short block lengths (meaning that most properties also front onto side streets, and remaining properties are not far from side streets) and to angled parking on connecting streets.

Pedestrian comfort and safety should be improved. This could take a variety of forms, including:

wider sidewalks (achieving Better Streets Plan minimum or, preferably, recommended standards)

reduced crossing distances, achieving by widening sidewalks and/or providing pedestrian refuges

improved circulation/connectivity (addition of mid-block crosswalks)

road diets/traffic calming measures

maintenance of/improvements to “buffers” from traffic


Designs should accommodate forecast growth in development. As identified in the selection criteria, this segment is in an where significant growth is projected, including significant residential growth likely to result in significantly greater demand for travel by all modes, but especially higher pedestrian volumes.

Open space, landscaping and other urban design elements should be enhanced. Existing designs and amenities are inadequate in terms of fostering an attractive and healthy public sphere. In particular, relatively narrow sidewalks (generally 10 feet) provide little opportunity for additional landscaping elements.

Capital cost/constructabilty should be factors. Cost considerations should be taken into account in assessing alternatives. Widening sidewalks and moving curb lines can significantly increase expenses, potentially requiring reconstruction of entire streets in order to ensure proper drainage.

Area-Wide Circulation Changes

In addition to redesign of 16th itself, a number of related circulation changes have been proposed to support the alternatives.

Grid Repair

Today, there is relatively little traffic in this segment of 16th Street. However, 16th is the only continuous through street between Mission Bay and the Mission and Castro Districts, and as Mission Bay is built out and Showplace Square is redeveloped, more traffic is to be expected. In order to remove one of the westbound travel lanes on 16th, and to prohibit left turns – as is assumed under all recommended alternatives – it would be desirable to provide alternative routes for auto travel between Mission Bay and the neighborhoods to the west.

While detailed designs have not been developed, a concept for “grid repair” has been developed. In general, this concept would convert the 15th Street and 14th/Alameda Street corridors in Showplace Square and the Mission into through routes. With a number of minor changes to the street network, 15th could serve as a through route between Mission Bay and Potrero Avenue (Bryant Street if Potrero Square were to be redeveloped at some future point), and 14th and Alameda could provide a continuous route between Mission Bay and Castro Street.

This concept assumes one or more crossings of 7th Street and the existing Caltrain right-of-way on the western edge of Mission Bay. The feasibility and exact locations of any such crossings would depend on design decisions still to be made in association with the California High Speed Rail project. One proposal developed by the City would reduce the cost of undergrounding of the rail right-of-way by replacing the 280 freeway viaduct north of 16th Street with an at-grade 7th Street boulevard. Under this concept, an existing grade-level crossing of the Caltrain tracks at Channel Street that is not aligned with any street to the west of 7th would be replaced with a new intersection at 7th and Hooper Street, and a planned future extension of Mission Bay Boulevard would be realigned to connect directly to Hooper across 7th.

Streets immediately to the west of 7th, including Hooper, are part of the South of Market grid and are thus oriented at 45 degrees to the cardinal. Just west of 7th, this grid connects, awkwardly, to the roughly north-south Mission/Potrero grid. Streamlining the connection between Hooper and 15th, at the intersection of the grids, would require a taking of a property. An extension of Alameda connecting to Hooper, meanwhile, would have to cross two industrial parcels. Alternately, any of the north-south streets in the area could be used to transition between Alameda and 15th.

To the west, Alameda currently dead-ends at Bryant Street, and 14th begins a block farther west (and slightly north) at Harrison. Connecting these two streets would require passage through existing private parking lots, including the parking lot in front of the Best Buy store on Division Street.


While the intent of the “grid repair” concept is to provide alternatives to 16th for auto travel between Mission Bay and the Mission District, it is not the intent of the concept that 14th, Alameda or 15th be converted to arterials. Rather, the objective is to use the repaired grid to distribute traffic over many streets, thereby reducing the burden on any one street.

17th Street Bicycle Corridor

Currently, City Bicycle Route 40 runs from Third Street west on 16th to Kansas, where it turns south for one block before continuing west along 17th Street. With the exception of the single block of Kansas, it features continuous Class II on-street bicycle lanes from Mission Bay through Potrero Hill to Potrero Avenue (then again from Treat to Church Street). However, several of the proposed alternatives would remove the existing bike lanes on 16th.

City policy prohibits the downgrade of bicycle facilities. However, it might be possible to satisfy this policy, and even potentially improve conditions for cyclists, by realiigning Route 40 onto 17th east of Kansas, and providing enhanced amenities there. 17th Street is parallel to 16th, approximately 470 feet to the south. For two blocks west of Kansas, between Kansas and San Bruno, the grade on 17th is somewhat steeper than on 16th. However, Route 40, with its bike lanes, is already on 17th Street at this point, and there are no bike lanes on the segment of 16th west of Kansas.

With the exception of one block to be discussed below, the cross-section of 17th east of Kansas consists of 10-foot sidewalks and a 46-foot unstriped roadway, with parallel parking on both sides. This is sufficient space to provide an 8-foot parking lane on each side, 6-foot bike lanes, and 18 feet of clear space for auto travel (alternately, the bike or parking lanes could be narrowed slightly to provide two striped 10-foot travel lanes; however, this would reduce the traffic calming benefits for cyclists and pedestrians). Conditions for cyclists might also be improved using traffic calming measures: conversion of two-way stop intersections to four-way stops, addition of corner bulb-outs and, potentially, a traffic diverter at De Haro, Vermont, or some other location.

On the block between De Haro and Kansas, the sidewalks widen to 12 feet, and the roadways narrows to 42 feet. On this block, addition of lanes would require removal of parking and/or loading from one side of the street, preferably the north side, as this is the configuration west of Kansas (the westbound bicycle lane is along the curb). There are currently approximately nine parking spaces on the north side of the street on this block. However, on the south side there is just one parking space; the remainder of the curb is reserved for loading (four to five spaces), and there is alarge curb cut leading to a loading dock entrance. No active uses front onto this block: on the south side is the side of a Whole Foods store, and on the north side is the side of an apartment building. It might be possible, then, to consolidate parking and loading on the south side of the street, and thus provide continuous bicycle lanes on 17th from the Mission District east to the edge of Mission Bay.

There are bicycle lanes extending south from the intersection of 7th and 16th on Mississsippi; Route 40 could easily transitiion from 16th to 17th at this point. Alternately, it might be possible to extend a pedestrian and bicycle path east from the end of 17th, under the 280 viaduct (or under a replacement structure, if the “bulletvard” is built) into Mission Bay, thereby allowing cyclists to bypass the busy corner of 7th and 16th. Development of Mission Bay Block 40 might block direct access to the first north-south street east of the freeway, Owens; however, it might be possible to have the path run along the western edge of the site, or through it if were planned as part of the development.

Alternatives Developed for 16th Street

The project team considered a total of nine alternatives. The complete list of alternatives is summarized in Figure 4.The alternatives selected for further development following preliminary screening are described in detail in the sections that follow.


Figure 4 16th Street: All Alternatives


1 Median Transitway

2 Median Transitway + Bike Lanes

3 Median Transitway + Bike Lanes + Curb Stops

4 Median Queue Jump + Parking

5 Median Queue Jump + Bike Lanes

6 Median Bikeway + Transit Lanes

7 Median Green

8 Reversible Lane

9 Side-Running Transit Lane + Bike Lanes

16th Street Alternatives Considered but Rejected

Alternatives 1, 2, 5, and 9 have been recommended for further consideration. Following is a brief summary of reasons for rejecting the remaining alternatives:

Alternative 3 was deemed inferior to the remaining median transitway alternatives, 1 and 2. This is because it would require buses to leave the median transitway and merge into the traffic lane at stops, a potentially problematic arrangement.

Alternative 4 was deemed inferor to the other median transit lane alternative, Alternative 5, because it would prioritize parking over bike lanes and wider sidewalks.

Alternative 6’s median bikeway was found to be problematic because cyclists might “pile up” in the bikeway waiting to turn left. Alternative 6 would also not allow for raised platforms at bus stops.

Alternative was rejected because its primary benefit, the opportunity for extensive landscaping, could also be provided in the wide sidewalks included in alternative 1. At the same time, the side-running transit lanes would not provide as much benefit as the median transitway proposed in Alternative 1.

Alternative 8 was the only alternative to provide a third travel lane; however, it would eliminate bike lanes while providing limited benefits for transit (it would not allow for raised platforms at bus stops), pedestrians, and the public realm.

16th Street Alternatives Recommended for Further Consideration

Figure 5 16th Street: Alternative Recommended for Further Consideration


1 Median Transitway

2 Median Transitway + Bike Lanes

5 Median Queue Jump + Bike Lanes

9 Side-Running Transit Lane + Bike Lanes


Alternative 1 (Median Transitway)

Figure 6 Alternative 1 Cross-Section (Typical)

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Figure 7 Alternative 1 Cross-Section (at Transit Stops)

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This alternative would provide major benefits for transit, with a median transitway and raised-platform island stops, features typical of Bus Rapid Transit service. In order to allow for island stops, sidewalks would have to be narrowed at corners with stops (it is assumed that stop spacing, while wider than existing, would be every five blocks, somewhat closer than in a standard BRT configuration); however, at other locations sidewalks would be very wide. There would be no continuous curbside parking or loading, although sidewalk cut-out “bays” could be accommodated (in this segment, there are relatively few existing retail uses, blocks are short, and there is generous parking on connecting streets), and existing bike lanes would be removed (see “17th Street Bicycle Corridor” section).


Selection of Alternative 1 would be contingent on a policy decision to approve removal of the existing bicycle lanes on 16th Street. The City’s policy is that existing bicycle facilities should not be downgraded; however, it might be possible to remain consistent with policy if a high-qualilty facility can be provided on 17th Street, which is parallel to 16th just one block away (see previous section, “17th Street Bicycle Corridor”).

Alternatives 1 and 2 feature a continuous, two-lane median transitway that autos and trucks could not legally enter at any point, or turn left across, the optimum condition for transit operations. In developing the alternatives, accommodating fast, reliable transit service was the highest design priorirty. Future transit volumes on 16th are forecast to be quite high: 14 buses in each direction during the peak hour on Lines 22 and 33 west of Connecticut (or nearly one bus every four minutes), and 10 buses per hour on Line 22 to the east; additionally, UCSF shuttles might be able to take advantage of exclusive transit lanes. The median transitway alternatives include island stops, which may be less comfortable for some waiting passengers than stops on the sidewalk. All stops in the recommended alternatives would feature raised platforms allowing level boarding , to speed the loading-and-unloading process.

Unlike Alternative 2, which includes bicycle lanes in addition to transit and auto lanes, Alternative 1 maintains a sidewalk width adjacent to transit stops of 12 feet, meeting the Better Streets Plan standard for a mixed-use street (in Alternative 2, sidewalks would be 10 feet wide at these points). At most points, Alternative 1’s sidewalks would be the widest of any alternative: 18 feet. Sidewalks of this width provide opportunities for generous landscaping, potentially including planter strips or double rows of trees. They also provide additional opportunities for sidewalk seating.

While it does not include continuous curbside parking and loading, Alternative 1 is unique among the alternatives in that it would allow for curbside loading at select locations using


sidewalk cut-out “bays” similar to those on Market Street. As the sidewalk at most points is 18 feet wide, an 8-foot bay would leave 10 feet of sidewalk (failing to meet the BSP standard; however, depending on the number of bays, this would be only over a short distance, it would not be at corners where pedestrian volumes are highest, and the sidewalk in these segments could be kept clear of all obstruction to maintain the pedestrian throughway). It should be noted that in Alternative 5, sidewalks are 17 feet wide, which might allow for bays.



Pedestrian + Major sidewalk widening

Transit ++ Much greater speed and reliability

Bike

-

Lanes would be removed (however, lanes and other improvements could be provided on 17th)

Auto Travel

-

2nd WB lane removed, left turns prohibited

Parking/Loading

-

Existing curbside spaces removed; however, sidewalks wide enough to allow for loading or parking bays

Urban Design ++ Landscaping opportunities from wider sidewalks

Cost/ constructability -

Relocation of curb lines


Alternative 2 (Median Transitway with Bike Lanes)


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This alternative is a variation on the previous, including bike lanes (which would be curbside, unlike the existing lanes in which cyclists risk dooring). Sidewalks would be narrower (although generally wider than existing).



Along with Alternative 1, Alternative 2 would provide the greatest benefit for transit speed and reliability. It would also represent an improvement for cyclists over the existing condition, as lanes would be adjacent to the curb rather than parked cars.

However, sidewalks would be widened only modestly (from 10 to 13 in most places, with reduction in a few blocks from 15 to 13 feet), and they would be narrowest at their busiest points, corners by bus stops.



Pedestrian / Sidewalks widened in some locations, left as-is or narrowed in others

Transit ++ Much greater speed and reliability

Bike + Risk of dooring eliminated

Auto Travel

- 2nd WB lane removed, left turns prohibited

Parking/Loading

-- Existing curbside spaces removed

Urban Design + Landscaping opportunities where sidewalks widened; median transitway fosters unique identity

Cost/ constructability --

Relocation of curb lines


Alternative 5 (Median Queue Jump with Bike Lanes)


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This alternative seeks to provide the benefits of a median transitway while requiring less space by including a center lane that could be used for “queue jump” pockets. Buses would be provided with an advance phase at signals allowing them to go ahead of traffic, and would block traffic while stopped. Unlike in Alternative 3, they would operate primarily in the travel lane, only merging into transit-only lanes, then back into travel lanes as necessary to bypass traffic. Signals could detect approaching buses and “hold” red lights so that buses would not merge into the


traffic lane just as the light turned green, thereby making them wait to merge back into the travel lane. Bicycle lanes are provided in both directions.


By dedicating space to transit strategically – only where it would provide the greatest benefit – Alternative 5 allows for significantly wider sidewalks than most other alternatives, 17 feet (immediately adjacent to stops, sidewalks would be 10 feet). It might also be possible to use the center, queue jump space for medians on blocks where queue jumps were not necessary. This alternative also features curbside bike lanes.

However, the queue-jump arrangement could complicate transit operations, and significant lateral sway would take place whenever buses changed lanes, reducing rider comfort. Stopped buses would block traffic, and there would inevitably be conflicts between transit passengers and cyclists where bike lanes separated transit stops from sidewalks.



Pedestrian ++ Major sidewalk widening; potential median refuges in some locations

Transit + Greater speed and reliability; possible operational challenges

Bike + Risk of dooring eliminated

Auto Travel

-


Parking/Loading

-

Existing curbside spaces removed

Urban Design ++ Landscaping opportunities from wider sidewalks; potential medians in some locations

Cost/ constructability -



Alternative 9 (Side-running bus lanes with bike lanes)


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This alternative would feature bike lanes along the curbs and bus lanes between the bike and travel lanes. At stops, bikes and buses would merge into a shared 15-foot lane, and limited medians could be provided.


Alternative 9 would combine side-running transit lanes with curbside bike lanes and slightly wider sidewalks (sidewalks behind bus stops would be six feet wide, just wide enough to satisfy ADA guidelines). It would also allow for limited medians adjacent to transit stops.

Side running bus lanes provide less priority for transit, and buses would have to wait behind vehicles turning right.

At bus stops, bike lanes would be dropped, and buses would proceed in a shared bus/bike lane. This operation presents the potential for conflicts between buses and bikes at merge points.

This alternative provides adequate space for raised platforms (with a slightly narrower 6’ of clear through space remaining on the sidewalk) and for short lengths of median at bus stops, These areas are also important pedestrian crossings that would benefit from the pedestrian refuges and addition of more trees. Sidewalks would be somewhat narrower (12’) than in the no-bike lanes alternative.



Pedestrian + Some sidewalk widening, refuges by bus stops

Transit + Greater speed and reliability

Bike + Risk of dooring eliminated; bikes would have to merge into bus lane at stops

Auto Travel

-


Parking/Loading

--

Existing curbside spaces removed

Urban Design + Landscaping opportunities from wider sidewalks; medians in some locations

Cost/ constructability --

Relocation of curb lines, medians


Summary Comparison of Alternatives

Figure 18 Summary Comparison of 16th Street Alternatives

1 2 5 9

Pedestrian + / ++ +

Transit ++ ++ + +


Bike

- + + +

Auto Travel

- - - -

Parking/Loading

- -- -- --

Urban Design ++ + ++ +

Cost/constructability

-- -- -- --



Appendix 1. Summary of 16th Street Alternatives Considered but Rejected

Alternative 3


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Unlike the other median transitway alternatives, in this alternative, sidewalks would not have to be narrowed at corners by bus stops. In order to do so, however, it requires buses approaching a stop to merge into the travel lane. Buses would be provided an advance phase at signals adjacent to stops, allowing them to go ahead of traffic. They would then block traffic while stopped, making it imperative that the loading and unloading process (“dwell time”) be made as efficient as possible (for all alternatives, it is assumed that raised platforms would be provided at bus stops, allowing for level boarding of buses). In order to reduce conflicts between cyclists and passengers getting on and off of buses, design treatments would be applied to bike lanes by transit stops.

This alternative was rejected due to concerns that the need to merge with vehicle traffic at stops would cause transit delay.

Alternative 4


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This alternative seeks to provide the benefits of a median transitway while requiring less space by including a center lane that could be used for “queue jump” pockets. As in Alternative 3, buses would be provided with an advance phase at signals allowing them to go ahead of traffic, and would block traffic while stopped. Unlike in Alternative 3, they would operate primarily in the travel lane, only merging into transit-only lanes, then back into travel lanes as necessary to bypass traffic. Signals could detect approaching buses and “hold” red lights so that buses would not merge into the traffic lane just as the light turned green, thereby making them wait to merge back into the travel lane.


This Alternative 4 is the same as alternative 3, but it would provide parking instead of bike lanes. This alternative was rejected because parking lanes are less important in this segment of 16th than other uses.

Alternative 6


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Alternative 6 would put a two-way cycletrack in the center of the street, with bus lanes along the curbs. This alternative was rejected because of concerns about the safety of bicycle turning movements.

Alternative 7


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This alternative would place a landscaped median in the center of the street. Alone among the alternatives, Alternative 7 provides opportunities for both a continuous landscaped median as well as regular pedestrian refuges. “Side-running” transit lanes could legally be used by private vehicles to turn right, and would thus be inferior to center-running lanes; however, the lanes would be superior to existing lanes elsewhere in San Francisco because they would not be adjacent to a row of parked cars, which generates additional conflicts. The median, if it has trees, also reduces the scale of the street to be more comfortable to pedestrians and can provide a median refuge at pedestrian crossings.

This alternative was rejected because its primary benefit, the opportunity for extensive landscaping, could also be provided in the wide sidewalks included in alternative 1. At the same time, the side-running transit lanes would not provide as much benefit as the median transitway proposed in alternative 1.

Alternative 8


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This alternative would use the central space for a reversible (according to peak direction) travel lane. This option was rejected due to concerns about operational feasibility and the urban design compromises required by the reversible lane. Existing vehicle volumes are also not peaked strongly enough to justify this treatment.

task 3.b: en trips priority corridors - preliminary street redesign alternatives

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hold red lights

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