whitemud drive - analysis of increasing the speed limit

ROUTING – Transportation Committee | DELEGATION - D. Wandzura/G. Cebryk May 21, 2014 – Transportation Services CR_586 of 5

Whitemud Drive - Analysis of Increasing the Speed Limit

Recommendation:

That the May 21, 2014, Transportation Services report CR_586, be received for information.

Report Summary

This report provides the results of a feasibility assessment and safety analysis for potentially increasing the 80 km/h posted speed limit on Whitemud Drive. Based on the analysis and review, the report recommends that the posted speed limit on Whitemud Drive remain at 80 km/h.

Previous Council/Committee Action

At the August 21, 2013, Transportation Committee meeting, the following motion was passed:

That Administration provide a report to Transportation Committee outlining:

a. results of further assessment and analysis of segregating corridors of Whitemud Drive for potential speed limit changes

b. the following statistics (including seasonal trend analysis) regarding Whitemud Drive:

• motorist speed by time of day • volume (with comparisons to other roads) • number of speeding tickets issued (both photo radar and manned) • number of collisions

c. information regarding changes required in Whitemud Drive road design to increase the speed limit

d. the noise impact of increasing the speed limit on Whitemud Drive

e. information regarding merging and exiting issues related to increasing the speed limit on Whitemud Drive

Report

The Whitemud Drive Posted Speed Limit Traffic Safety Assessment and Feasibility Analysis report (Attachment 1) is attached for information. A comprehensive analysis was conducted to determine the suitability of a posted speed limit increase based on six factors:

1. Segmentation of Whitemud Drive.

6. 2

PLEASE RETAIN THIS REPORT FOR FUTURE MEETINGS


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2. Transition zones. 3. Collision speed, volume and enforcement statistics. 4. Road design. 5. Noise and emission impact. 6. Merging and exiting issues.

Based on this comprehensive technical review, the City of Edmonton, Office of Traffic Safety is not recommending an increase in the 80 kmh/h posted speed limit on any segment or throughout the entire length of Whitemud Drive.

This recommendation is based on the following:

1. The segregation of Whitemud Drive into corridors, as identified in Appendix A, Figure A-1 and A-2 of the report, confirms high rates of collisions throughout which taper on the east and west end segments of Whitemud Drive. Zone D, C-1, and C-2 could potentially be increased to 90 km/h; however, other major infrastructure impediments would significantly reduce traffic safety and are covered in the transition zones from Whitemud Drive connecting with external roadways.

2. The transition zones of Whitemud Drive on the east end and west end to external infrastructure have similar as well as separate traffic safety issues. The transition zone on the east boundary of Whitemud Drive connects Zone C-1 and Zone D with the Anthony Henday Drive Interchange and turns into Township Road 522. Traffic is restricted to one through lane, a reduction of speed to 70 km/h, and a set of traffic lights at Range Road 233. This often results in stopped vehicles queuing for the traffic signal with backed up traffic onto the Anthony Henday Drive Interchange and extending west onto Whitemud Drive. The transition on the Whitemud Drive west boundary from Zone C-2 connects with the Anthony Henday Drive interchange and is quickly reduced to one through lane at 80 km/h. This portion of Whitemud Drive west of Anthony Henday Drive has a high density of housing on either side and accommodates a large volume of traffic for two major businesses south and southwest of Whitemud Drive and 231 Street. The traffic signals at 231 Street control one through lane westbound, as well as accommodates a large volume of turning traffic. Both the east and west Whitemud Drive connections to Anthony Henday Drive and external roadways have traffic safety issues relating to property damage, injury, and one fatal collision.

3. Automated enforcement violation speeds are overwhelmingly consistent at about 100 km/h which is 20 km/h over the posted speed limit. With the present high frequency of collisions along Whitemud Drive, any increase in the posted speed limit will further amplify traffic safety concerns relating to vehicles entering, exiting, and merging onto Whitemud Drive.

4. Edmonton Police Service’s manned enforcement along Whitemud Drive shows a fluctuation in speeding violations along different segments and also confirms speeding along the entire stretch of the roadway.


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5. The two primary causes of collisions along Whitemud Drive relate to following too closely and changing lanes improperly. The distribution of these collisions is concentrated in the right turn bay/ramp, the first lane from the curb, and the second lane from the curb. Collisions in the right turn bay/ramp areas are potentially related to speed differential of through traffic and ramp traffic. The Following Too Closely and Changing Lanes Improperly collisions in the curb lane and second lane from the curb also suggest conflict points with slower entering and exiting traffic and through traffic.

6. The Collision Rate Comparison Table below (2010 - 2012) confirms that Whitemud Drive has a significantly higher collision rate than similar roads.

Intersection Collision Rate (collisions per million vehicles entering the

intersection)

Midblock Collision Rate (collisions per million vehicle-

kilometers)

Whitemud Drive 1.021 1.695 Anthony Henday Drive 0.281 0.373

Yellowhead Trail 0.977 1.190

7. Transportation Services report CR_238 (Whitemud Freeway Speed Limit Changes) summarized critical geometric constraints that support the present 80 km/h posted speed limit. Major road design changes would be required in order to increase the speed limit such as:

a. Re-alignment of horizontal curves north of Quesnell Bridge and south of 53 Avenue.

b. Re-design the left-hand exiting ramp at Terwillegar Drive into right-side exiting and reconstruct the ramp.

c. At extremely high cost, close some entrances/exits to increase spacing of interchanges from 91 Street to 111 Street; and

d. Re-design several underpasses and vertical curves with limited sight distance, such as those at 106 Street and 111 Street.

8. Transportation Services report 2009TD0150 (Whitemud Drive/Quesnell Bridge Noise Attenuation) confirms noise levels on Whitemud Drive are at levels which may require noise attenuation counter-measures under Urban Traffic Noise Policy (C506) if there are any increases in the current noise level, particularly at locations which are adjacent to residential areas. An increase in the posted speed limit along Whitemud Drive could potentially increase the noise levels which may require installation of noise attenuation walls. Exhaust emission levels would also increase for Carbon Monoxide and Nitrogen Oxide.


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9. The current Geometric Design Guide for Canadian Roads (TAC, 1999 Edition) suggests that any increase in the posted speed limit would require extended acceleration and deceleration lanes at specific locations.

10. The present traffic operating profile of Whitemud Drive confirms a speed gap between through traffic and traffic using the on-ramps and off-ramps. An increase in the posted speed limit will increase the speed gap which will increase the potential conflict areas for entering, exiting, and merging traffic.

11. The proposed higher density of land use of urban areas along Whitemud Drive will require more frequent entering, exiting, and interweaving of traffic which will increase traffic congestion and reduce traffic safety. 12. The Edmonton Police Service Traffic Section was provided a copy of this assessment and confirmed they do not support increasing the Posted speed limit on Whitemud Drive.

In conclusion, the above traffic safety data and analysis confirms that Whitemud Drive has a significantly greater number of collisions than comparable similar roads. This traffic safety assessment does not support any change in the present posted speed limit.

From an engineering perspective, specific sections of Whitemud Drive have design speeds that could support a posted speed limit of 90 km/h; however, based on the collision data, speed data and noise consideration, an increase in the posted speed limit is not recommended.

Should City Council consider increasing the posted speed limit along specific segments, the east segment from 75 Street to 17 Street has a design which could allow an increase in the posted speed limit. Similarly, the segment from 159 Street to Guardian Road has a design which can accommodate a posted speed limit of 90 km/h.

Administration does not recommend a change to the posted speed limit throughout Whitemud Drive.

Corporate Outcomes

The increase in the Posted Speed Limit will impact several Corporate Outcomes namely: 1. Preserve & Sustain Edmonton's Environment 2. Improve Edmonton's Liveability 3. Transform Edmonton's Urban Form 4. Shift Edmonton's Transportation Mode and Reduce Safety 5. Ensure Edmonton's Financial Sustainability


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Attachments

1. Whitemud Drive Posted Speed Limit Traffic Safety Assessment and Feasibility Analysis Report

whitemud drive - analysis of increasing the speed limit

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