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  • CHAPTER 6

    URBAN TRANSPORTATION PLANNING3

    The environment in which transportation professionals operate haschanged dramatically during the past 10 years. Throughout the 1960s,the urban transportation "problem" was perceived almost exclusively asone of highway congestion. In response, most transportation plannersand engineers considered as their first priority the accommodation ofthis rising traffic demand by planning new or expanded expressways.This problem definition has changed, however, and so too have thetypes of solution strategies that transportation planners and designersmust consider. The "new" urban transportation problems include at thevery least the relationship between transportation and: (1) Energy con-sumption; (2) air quality; (3) equity; (4) safety; (5) congestion; (6) land-useimpact; (7) noise; and (8) more efficient utilization of fiscal resources (1).The different planning methodologies used to address each of theseareas, the need to interact with professionals in other disciplines, therequirement to include public input throughout the planning process,and the desire to put transportation planning in the context of theover-all planning process for a metropolitan area make transportationplanning an extremely complex process.

    The planning process has been made even more complex by arecent shift in the focus of such planning from large-scale, capital-intensive projects to smaller scale, operational improvements whichseek the more efficient use of the existing transportation network. Thetraditional analysis methodologies and the institutional environment forurban transportation planning have thus changed significantly. Now,more than ever, there is a need to have those who do the planninginteract with those who design and implement, so that each understandsthe contraints under which the other operates.

    This chapter is organized to address many of the new characteris-tics of transportation planning. The introductory section will examinethe role of transportation in an urban setting, some of the importantcharacteristics of transportation that affect planning efforts, and thetypes of issues that transportation planners and designers can expect toface during an analysis. The second section will review the majorcomponents of a short-range planning process and the types of projectsthat are typically the product of such a process. Specific attention will begiven to the role of the planner, designer, and policy maker in this typeof planning activity. The third section will address issues similar to those

    aPrepared by Michael D. Meyer, Massachussetts Dept. of Public Works, Boston,MA.

    116

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  • URBAN TRANSPORTATION PLANNING 117

    in Section 6.2 except that the focus will be on long-range planning, i.e.,what types of transportation actions should we be considering now thatwill have an impact in 20-25 years? Section 6.5 will look at how projectsare programmed for implementation, some of the schemes that are usedfor prioritizing, and the relationship between programming and thepolitical environment. The typical process for project development, i.e.,how projects are identified, the procedures that must be followed forfurthering the project, project design considerations, and project plan-ning implementation procedures will be described in Section 6.6. Thepurpose of this section is to integrate much of the material presented inthe preceding sections within the context of a single project.

    6.1 TRANSPORTATION IN AN URBAN SETTING

    Basic to an understanding of transportation are the characteristicsof urban travel that in many ways define the scope of urban transpor-tation problems. Five such characteristics that will be considered in thissection include:

    1. Temporal distribution of urban travel.2. Type of trips made.3. Modal distribution of urban trips.4. Environmental impact of transportation facilities.5. Relationship between land use and transportation.

    Where appropriate, examples will be given of the types of trans-portation strategies that are now being considered to address some ofthe problems associated with each characteristic.

    6.1.1 Temporal Distribution

    Congestion has often been identified as the major transportationproblem in today's cities. Put simply, congestion denotes a condition ofany transportation facility in which service demand exceeds capacity,resulting in increased delays for the users of that facility. This problembecomes apparent if one looks at the hourly variation of urban persontrips by mode during the day (see Fig. 6-1). The demand for transpor-tation service during the morning and afternoon peak periods in manycases causes the transportation system to reach high levels of conges-tion. The solution to this problem during the early 1960s was to expandthe capacity of the highway network so that the increased vehiculardemand could be accommodated. In most areas, however, such solu-tions are no longer feasible because of the disruption such expansionwould cause neighboring areas, the large cost associated with construc-tion, and the increasing demands on transportation funds for othertypes of projects.

    Other strategies that are currently being considered to handle the

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  • 118 URBAN PLANNING GUIDE

    Fig. 6-1. Hourly variation in travel (16)

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  • URBAN TRANSPORTATION PLANNING 119

    peaking problem include: (1) To "spread" the peak by arranging workhours such that large groups of employees arrive at different times(variable work hours and flexi-time), and (2) to increase the averageoccupancy level of vehicles entering a downtown area (ridesharingprograms, preferential treatment for buses and carpools, and auto dis-incentive projects). These types of solutions may be more cost effectivethan permanent capacity expansion.

    6.1.2 Trip Purpose

    Trip purpose is also an important characteristic of urban travelbehavior. The largest percentage of trip purposes to the Central BusinessDistrict (CBD) is the home-to-work trips which because of their time oftravel usually contribute most to transportation congestion. The secondlargest category of trips are those taken for social and recreationalpurposes, which taken in conjunction with shopping trips, account foras many home-based trips as the work trip. The home or dwelling unitis the primary origin of most trips, with more than three-fourths of allurban trips originating from or destined for the home (3). Unique travelpatterns are also associated with special purpose activities such ashospitals, universities, and high density business districts (13).

    6.1.3 Modal Distribution

    One of the most visible characteristics of the transportation systemin this country is the dominance of the automobile. From 1950 to 1975,the proportion of American households owning at least one car rosefrom 52% to 83% (16). Meanwhile, vehicle miles of transit servicenationally declined by 37% (25). However, in some cities the percentageof trips to downtown areas served by transit is quite large. Further, giventhe existing policy trend toward discouraging auto use in metropolitanareas, and the likelihood of fuel shortages in the future, the role of transitand other high occupancy vehicles is likely to become more important.

    In the transit field, there has been increased public pressure onproviding service distribution according to need, focusing specifically onthe mobility deficits of the physically handicapped, the elderly, and thepoor. In general, the elderly and poor rely more heavily on transit andtaxi travel than the general population does (see Tables 6-1 and 6-2).Effective methods for enhancing the mobility of these groups include: (1)Direct payment of subsidies in the form of vouchers or transit farediscounts; (2) increased demand responsive transportation services; (3)redesign of fixed route service to serve the needs of low-income travel-ers; and (4) a restructure of transit fares (1).

    6.1.4 Environmental Impact

    The characteristic of transportation that has gained the most publicattention during recent years has been the impact of transportation

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  • 120 URBAN PLANNING GUIDE

    TABLE 6-1 Trips Per Capita and by Mode, 1970 (1)

    Mode0)

    Auto driverAuto passengerMotorcycleTruck (driver or passenger)Subtotal: private vehicleTransit busRapid transitCommuter railSchool busTaxiSubtotal: public transportationOther (airplanes, etc.)Total

    Percentageof All Trips

    Persons65 andover(2)

    53.435.9

    4.293.54.30.50.10.60.66.10.4

    100.0

    Allpersons16 andover(3)

    62.625.70.26.0

    94.52.80.90.21.20.35.40.1

    100.0

    TripsPer Capita

    Persons65 andover(4)

    201135

    16352

    162

    22

    221

    375

    Allpersons16 andover(5)

    531218

    251

    8022482

    102

    461

    849

    TABLE 6-2 Transit Accessibility by Income, 1970 (1)

    Annualhousehold

    income group(1)

    Under $5,000$5,000-9,999$10,000-14,999Over $15,000All households

    Distance to NearestPublic Transportation (in Blocks)

    Lessthan 1,in per-

    centage(2)

    30.320.915.513.321.3

    1-2,in per-

    centage(3)

    34.533.229.323.730.8

    3-6,in per-

    centage(4)

    17.418.318.320.618.6

    Over6,

    in per-centage

    (5)

    9.215.520.625.516.6

    Noneavail-able,

    in per-centage

    (6)

    8.411.716.315.912.4

    facilities and travel on the natural environment. The transportationimpact on air quality, for example, emerged during the late 1960s as asignificant political issue and has resulted in several federal regulationsthat guide transportation and air quality planning at the local level.Automobiles account for at least 80% of carbon monoxide (CO) and lead

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  • URBAN TRANSPORTATION PLANNING 121

    emissions in most metropolitan areas; about 70% of hydrocarbon emis-sions (HC); and about 50% of the nitrous oxide emissions (NOX). Manyof the severe problems with these primary pollutants result when theychemically combine under favorable meteorological conditions to formsecondary pollutants. For example, nitrous oxide emissions react withhydrocarbons in sunlight to form photochemical oxidants (smog) thatare not only dangerous to health but seriously affect visibility and theesthetics of a metropolitan area. The automobile is the primary source forboth pollutants necessary for this reaction. The types of transportationactions that can be implemented in a metropolitan area, however, canhave varied effects on pollutant emissions. As shown in Fig. 6-2, forexample, as average speed increases, HC and CO emissions decreasewhile NOV emissions increase.

    Fig. 6-2. Air pollutant emissions as function of speed

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  • 122 URBAN PLANNING GUIDE

    Transportation's impact on energy consumption has also receivedclose scrutiny during the past several years. Gasoline accounts for nearly40% of all oil used in the United States, and as the availability of oilbecomes increasingly scarce, the style of personal transportation couldchange significantly. Studies have shown that public transit andvanpools are the most energy efficient when compared to all othermodes (30). However, most analysts believe that transit alone cannotcontribute substantially to a national reduction of petroleum importsbecause of the low base from which it currently operates, which is at lessthen 3% of urban passenger travel (7). To truly have an impact, atransportation and energy plan would have to combine automobiledisincentives with incentives to use transit service. The planner musttherefore view effective transportation strategies as the integration ofseveral transport actions, each affecting one component of the system,but which in total achieve the desired objective (6,14).

    6.1.5 Land Use and Urban Development

    Transportation and urban development are closely related in amultitude of ways. First, transportation is a critical factor in makingparcels of land available for development. A central characteristic ofmost urban networks is that they serve major activity centers which area focus for transportation services and are junctions or terminal pointsfor the congested high traffic volume corridors. This relationship pro-duces the high densities of land use in metropolitan areas, and, in turn,the high values of land observed in these centers. Although transpor-tation was clearly a dominant factor in the rapid suburbanization thathas occurred during the past 25 years, the highway network in mosturban areas is now so ubiquitous that it is doubtful if transportationmeasures alone can significantly impact metropolitan patterns of landdevelopment. Only through such measures as managing the access tothe highway network or using local zoning controls related to transpor-tation actions could a significant impact on regional land use be made.Where considerable potential for high-density development exists, how-ever, and other governmental levers such as zoning and tax incentivesare utilized, transit and traffic investment could play an importantsupporting role.

    A second factor in the transportation and land use relationship isthat transportation facilities occupy land. Between 25% and 45% of theland in central cities (approximately 3% nationwide) is devoted tohighways, streets, and parking lots. It was indeed this requirement forlarge areas of land in densely populated areas and the necessity ofdisplacing large numbers of people that caused some of the reactionagainst large-scale highway construction during the late 1960s.

    The land use and transportation relationship thus becomes animportant component in the transportation planning process. This proc-ess must include at the least an inventory of land usage and an evalu-ation of its effect on the performance of the transportation system.

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  • URBAN TRANSPORTATION PLANNING 123

    Indeed, most transportation studies use data on land development bytraffic analysis zones to predict the number of trips moving between thezones. More will be said about this in the following two subsections.

    6.1.6 Institutional Framework for Transportation Planning

    Ever...