tazul islam, ph.d. city of edmonton office of traffic safety · 8th international conference on...

40 km/h Speed Limit : Experiences & Lessons Learnt Tazul Islam, Ph.D.

City of Edmonton Office of Traffic Safety

8th International Conference on Urban Traffic Safety

April 25-28, 2016 | EDMONTON, ALBERTA, CANADA



Outline

Program Background

Community Selection

Program Details

Data Collection

Evaluation Methods

Results

Conclusions

Q & A



Background Local and international factors to lend support for a speed limit reduction

Speeding/careless driving is the top community problem

City Councilors were receiving ongoing and sustained speeding complaints

Need for a broader systemic solution

Evidence of speed-collision relationship

Discussion in the 1st conference in 2009



Background

City Council’s Transportation Committee asked to review the potential of

reducing speed limits on residential roads

The OTS was identified as the lead agency for this initiative

Stakeholders workshop in June 2009

Edmonton Federation of Community Leagues (EFCL)

Edmonton Public School Board

Edmonton Catholic School Board

Alberta Motor Association

Edmonton Police Service (EPS)

The EFCL also conducted an online speed reduction survey

Recommendation to reduce the limit to 40 km/h or less on residential roads

On October 6, 2009, City Council approved the pilot project

investigate the effect of lowering the posted speed limit to 40 km/h



Neighborhood Selection The selection process started in Oct 2009 and ended in Feb 2010

New 40 km/h sign installed in April 2010 and kept covered until the bylaws

came into effect on May 1, 2010



Neighborhood Selection

Old (1950’s/1960’s) Communities




Grid-based Communities




New (1970’s/1980’s) Communities



Program Details Pre-and post-communication plan to keep stakeholders informed

Media campaign (local TV, print, radio, online)

A variety of educational and enforcement measures



Data Collection Speed and traffic survey data

24/7 data collection for treated, control and adjacent communities

A total of 73 locations

Before (April); After (May to October)

25 million individual vehicle data records

Collision data

Motor Vehicle Collision Information System (MVCIS)

3-year before and 3-year after data

Community perceptions

Random telephone survey

Prior to project initiation (Mar) and the end of the project (Nov)

A total of 300 residents in the pilot communities

Others

Road geometry

Neighborhood characteristics

Census data



Evaluation Methods

Before-after evaluation methodology was adopted

Speed and traffic volume

Before-after evaluation with control group

Collision

Bayesian before-after evaluation

Public perception

Simple before-after evaluation



Speed & Traffic Evaluation Results

≈4 km/h reduction in

mean and 85

percentile speed

≈ 4% reduction in

traffic volume



Speed & Traffic Evaluation Results



Collision Evaluation Results

13

24

12

0

5

10

15

20

25

30

Total Severe PDO

% C

olli

sio

n R

ed

uct

ion



Perception Evaluation Results



Follow-up Survey Telephone interviews between July and August, 2011

2,044 interviews were completed



Conclusions

• Posted speed limit reduction was successful in terms: – Speed

– Traffic volume

– Crash

– Perception

• New Speed Reduction Policy – 67% community support

• Recent discussions



Thank You! [email protected]

mailto:[email protected]



Questions?

tazul islam, ph.d. city of edmonton office of traffic safety · 8th international conference on...

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