INDUSTRY STUDIES
Over the past several years, a lot of research has been conducted on traffic calming measures – what’s effective and what is not. Clicking on the titles of the following entries takes you directly to the third-party studies being summarized. We’ve included a number of research findings on the effectiveness of radar speedcheck signs and other means of slowing traffic. For questions, comments or additions to these links, please e-mail us at experts@stopspeeders.org
1. Study Reports On The Effectiveness Of Photo Radar And Speed Display Boards
Road Injury Prevention & Litigation Journal
Study conducted by TranSafety Inc.
May 1, 1998
“…an independent source for publications and information on road transportation and safety.”
Excerpts: “While both photo-radar and speed display boards can be effective in
reducing vehicle speeds, display boards offer better overall results."
2. Evaluating Effectiveness of Dynamic Speed Display Signs in Transition Zones Of Two-Lane Rural Highways In Pennsylvania
Transportation Research Board Annual Meeting 2009 Paper #09-0171.
Published by the National Academy of Science, Transportation Research Board.
January 2009
Excerpts: The results of the analyses indicate that the dynamic speed display signs are effective in reducing free-flow speeds by an average of 6.4 mph (10.3 km/hr) while in place and activated.
3. Evaluation of Four Recent Traffic And Safety Initiatives
Volume IV. Increasing Speed Limit Compliance in Reducing Speed School Zones
Report No. UT-05.13
June 2005
Prepared for Utah Department of Transportation Research And Development Division
Submitted by Brigham Young University Department of Civil & Environmental Engineering
Excerpts: Immediately after the sign was installed, the SMD proved to reduce the average speed from 44.5 to 35.3 mph, the percentage of vehicles exceeding the school zone speed limit (35 mph) from 95.3 percent to 34.1 percent...
4. Evaluation of Dynamic Speed Display Signs
Journal Of The Transportation Research Board, Volume 1918,
Study conducted by Texas Transportation Institute, Texas A&M University System
Published by Transportation Research Board of the National Academies
2005
Excerpts: Sites evaluated included a school speed zone, two transition speed zones in advance of a school speed zone, two sharp horizontal curves, and two approaches to signalized intersections on high-speed roadways.
5. Effectiveness of Dynamic Speed Display Signs (DSDS) in Permanent Applications Project Summary Report 0-4475-S, 2004.
Project Summary Report 0-4475S
Texas Transportation Institute
Texas A&M University
2004
Excerpts: After the DSDS was installed, the average speed decreased more than 9 mph. Furthermore, average speeds were still 9 mph lower when researchers returned to that site and measured speeds four months after DSDS installation.
6. Guidelines for Selection of Speed Reduction Treatments at High-Speed Intersections
National Cooperative Highway Research Program
NCHRP Report 613
2008
Excerpts:…dynamic warning signs reduced speeds significantly at the three high-speed intersection approaches tested…/…Roundabouts (also) have the potential to lower speeds to allow drivers more time to react to potential conflicts.
7. Use of Speed Display Trailers In Work Zones
(a review of literature found in )Work Zone Safety Toolbox
Maryland State Highway Administration, Office of Traffic & Safety
August 2005
Excerpt: The speed display trailer is an effective speed reduction measure in work zones...speed limit compliance is increased by 10 to 40 percentage points.
8. Comparative Study Of Speed Reduction Effects Of Photo-Radar And Speed Display Boards
Journal of the Transportation Research Board, Volume 1640.
Study sponsored by: Automobile Club Of Southern California
1998
Excerpt: The three cost-effectiveness estimates generated showed that the unenforced speed display board was the most cost-effective; the enforced display board came in second; and the photo-radar placed third.
9. Evaluation of Speed Displays And Rumble Strips At Rural-maintenance Work Zones
Transportation research record ISSN 0361-1981
National Research Council, Washington, DC, Presented
2001
Study conducted by the Texas Transportation Institute, Texas A&M University System
Excerpt: The speed display was generally more effective than the rumble strips at reducing speeds in the advance warning area.
10. Efficacy of Speed Monitoring Displays in Increasing Speed Limit Compliance in Highway Work Zones
Thesis study,
Brigham Young University
2003
Excerpt: The majority of drivers surveyed had positive reactions to SMDs, reporting that they feel SMDs are accurate, not distracting and not difficult to read.
11. Innovative Traffic Control Devices for Improving Safety at Rural Short-Term Maintenance Work Zones
Texas Transportation Institute Texas A&M University System
2008
Excerpt: The speed display trailer produced the largest speed reductions of all the devices tested.
12. Guidelines for Selection of Speed Reduction Treatments at High-Speed Intersections
NCHRP Report 613
National Cooperative Highway Research Program
2008.
Excerpt: Dynamic warning signs reduced speeds significantly at the three high-speed intersection approaches tested through the NCHRP 3-74 project.
13. Stationary Radar Sign Program Report
Study by the city of Bellevue, WA
2005
Excerpt: …the majority of signs continue to experience speed reductions of significant value up to four years after installation.
14. Traffic Calming Solutions – A Survey Of Safety Professionals
Sponsored by Information Display Company
2007
Excerpt: Driver feedback signs were ranked as having the most immediate and long-lasting effect on calming traffic. This was followed in order by "Police with radar guns," "speed bumps," "static speed limit signs," and "rumble strips
OTHER LINKS
AATC - Traffic Calming Reform
Excerpt from web site: Traffic calming devices which use vertical & horizontal "thrusts or deviations" can and have caused the following: death, injury, pain, discrimination, denied street access for the disabled, increased air pollution and have drastically slowed emergency response times putting you and your family at risk!
Traffic Calming State of the Practice
Slide Show Presentation
Prepared by Reid Ewing
For the Institute of Transportation Engineers
September 1999
Excerpt from presentation:This slide show contains the visual aids and instructor notes for a 1-day seminar on Traffic Calming.
The Professional Engineer
Excerpt from Web Site: TheProfessionalEngineer.com was started in November 2007 to provide the professional engineering community with a web site to present information of interest, provide links to pertinent industry and government web sites, and to allow for discussion of topics of interest to this community.
