Most drivers and pedestrians know from their own experiences that intersection safety is a big problem. The statistics come as no surprise. Briefing Sheets developed by the US Institute of Traffic Safety Engineers for "the media, decision-makers, the general public and others" cite the following:
* in 2002 approximately 3.2 million intersection-related crashes occurred representing 50 percent of all reported crashes. (40 to 50 percent is the range generally cited for this measure.)
* 9,612 fatal intersection crashes occurred representing 22 percent of total fatal crashes
* 1,066,000 intersection-related injury crashes occurred representing 55.3 percent of all injury crashes
* 2,092,000 "Property Damage Only" intersection crashes occurred representing 48.1 percent of all PDO crashes
* the total annual societal cost for intersection crashes was approximately $96 billion
* the number of fatal crashes at traffic signals is rising faster than any other type of fatal crash nationwide
* despite improved intersection design and more sophisticated applications of traffic engineering measures, the annual toll of human loss due to intersection crashes has not substantially changed in more than 25 years
The distribution of fatal crashes at the various types of intersections-signalized, stop sign only, and no traffic control, i.e., with no control signal or stop sign on the street being crossed-is closer than might be anticipated at 32%, 37% and 28% respectively. According to these numbers stop sign intersections are the most dangerous while signalized intersections are only slightly better but surpassed by no control intersections.
These statistics counter logical expectations (we think) but wouldn't surprise Hans Monderman. Road Rules readers will recall Monderman as the world-renowned traffic engineer who dislikes traffic signs, advocates the counterintuitive notion that the safest roads are those that seem the most dangerous, and designs intersections that are "utterly ambiguous" traffic circles: without lane markings, speed limit signage, right-of-way signage or curbs separating the car zone from the pedestrian zone.
The distribution of fatal intersection crashes by manner of collision, however, accords with reasonable predictions. Side impact crashes predominate-at signalized intersections, for example, yellow and red light runners T-boning left turners and green light jump starters-accounting for over 60 percent of fatal intersection crashes. Rear-end and head-on crashes each account for 5 percent. 28% -almost one in three fatal crashes at intersections-do not involve a collision with another motor vehicle in motion, a category that presumably incorporates pedestrian and cyclist fatalities.
While improvements in road design, traffic engineering, safety laws and regulations, enforcement efforts, and driver and pedestrian education are all advanced as potential 'solutions' to the problem of intersection safety, the leading cause of urban crashes-red light running-results from a complex mix of inadvertent and intentional behaviours shading from driver error-failing to properly estimate the signal interval time, for example-all the way to criminal carelessness. Engineering and enforcement countermeasures should help with reducing inadvertent red light running. Controlling willful disregard-a type of driver behaviour seen more and more-will be the toughest challenge.
Cedric Hughes of Hughes and Company Law Corporation, with contributions from Leslie McGuffin, LL.B., writes a weekly column on traffic advice for The VOICE. "The Road Rules" strives to provide helpful information about driving in British Columbia. We welcome your comments on our published articles and your suggestions for topics you would like us to address. Please email: eginter@hughesco.com. Phone: (604) 602-1818. Punjabi and Hindi: (604) 897-0207.
Email: cedric_hughes@hughesco.com
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