I have conducted a
typology and analysis of all police-reported car-bike collisions for the last six years here in Cary, NC, population 100,000.
The Cary Police department provided me 75 Cary Police reports dated from March 7, 1997 to November 21, 2002. Of these 75 reports, 73 included enough information to determine the positions and directions of the vehicles during the collision. Note that many of these collisions involved injuries but none involved fatalities. I classified these 73 collisions by the following types, in order of frequency, which I believe are useful for understanding the problems and potential preventative measures. Note that a couple of these numbers may change slightly when further investigation is completed:
WRONG WAY: 36 collisions (49%) involved bicyclists traveling on the left half of the highway against the ordinary flow of vehicular traffic. Nearly all of these bicyclists were operating on the
sidewalk prior to the collision. 30 of these wrong-way bicyclists were struck by automobile drivers who were turning right onto the roadway from a stop sign, red light, or driveway. These drivers were probably looking to the left prior to the collision.
RIDE OUT: 12 collisions (16%) involved bicyclists who rode out across the roadway or private vehicular area where the motor vehicle driver had the legal right of way and could not stop in time. Most of these collisions occurred at intersections or driveways.
LEFT CROSS: 7 collisions (9.6%) involved motor vehicle drivers who turned left across the path of the cyclist (who was traveling in the correct direction for vehicular traffic, on the opposite side of the road from the oncoming motorist) and violated the cyclist's legal right of way.
RIGHT HOOK: 5 collisions (6.8%) involved motor vehicle drivers who were traveling in the same direction as the bicyclist when the motor vehicle drivers turned right and collided with the bicyclist. Four of these bicyclists were operating on the roadway; one was operating on the
sidewalk prior to the collision. One of the bicyclists on the roadway was attempting to overtake the automobile driver on the right. One of the motor vehicle drivers attempted to turn right from the left through lane immediately after passing the bicyclist who was using the right through lane.
DRIVE OUT (PROPER DIRECTION CYCLIST): 5 collisions (6.8%) involved motor vehicle drivers who drove out across the roadway where the cyclist (who was operating in the correct direction for vehicular traffic on that side of the highway) had the legal right of way. Four of these bicyclists were operating on the roadway; one might have been on the
sidewalk but the police report does not specify.
PASSING TOO CLOSELY: 5 collisions (6.8 %) involved motor vehicle drivers who attempted to pass bicyclists at unsafe distance, resulting in collision. More on these collisions follows below.
BICYCLIST LOSES CONTROL: One collision (1.4%) occurred when a cyclist lost control and crashed into the side of a motor vehicle that was stopped at a stop sign.
BICYCLIST TURNS LEFT FROM CURB: One collision (1.4%) occurred when the cyclist attempted to turn left from the curb, suddenly and without looking backward, directly in front of a motor vehicle driver who was overtaking in the same direction.
BICYCLIST TRAPPED BY SIGNAL: One collision (1.4%) occurred when a traffic signal changed before a bicyclist completed crossing an intersection.
Given the public paranoia about overtaking-type collisions, and the scale of the engineering investments proposed or committed to their prevention, the 5 collisions involving motorists passing too closely deserve extra attention. Here are the details of these collisions:
One overtaking collision occurred on a two-lane section of Davis Drive where a raised concrete median was installed. The pavement width between the raised concrete median and the drop to the soft shoulder is 11 feet. The travel lane striped within this space is 10 feet wide. (I made these measurements myself.) The driver of a motor vehicle towing a trailer sounded his horn at the bicyclist in the travel lane, and then attempted to squeeze past between the median and the bicyclist. The bicyclist slipped off the pavement as the tow vehicle squeezed past, then lost control on the soft shoulder/pavement edge and collided with the trailer as the driver moved to the right before the trailer had cleared the bicyclist.
One overtaking collision occurred on a rural two-lane section of Carpenter Upchurch Road. The travel lanes in this section are striped 10 feet wide with two-foot paved shoulders. The total asphalt width is 24 feet. The driver of a motor vehicle towing a trailer attempted to pass on a right curve. The driver moved back to the right side of the roadway before the trailer had cleared the bicyclist. The trailer collided with the bicyclist.
One overtaking collision occurred on a four-lane section of Kildaire Farm Road just south of W. Cornwall Road. The rightmost travel lane here is 11 feet wide. The driver of a van attempted to pass the bicyclist in the same narrow lane. The mirror of the van struck the bicyclist. The van left the scene without stopping.
One overtaking collision occurred on S. Walker street, a two-lane 25 mph road that is 25 feet wide. The police report shows that the 10-year-old bicyclist was in the center of the roadway when the collision occured. Given the unusual location of the collision, the slow travel speed of the motorist, and the young age of the cyclist, it is possible that the cyclist made a movement that contributed to the collision, i.e. turning left into a driveway. More investigation is needed to determine the cause of the collision.
One overtaking collision occurred on westbound Walnut Street just before the intersection with US/1 and Buck Jones Road. I have not yet measured the travel lane width at this location. The overtaking motorist "tapped the back tire" of the bicyclist shortly before making a right turn onto Buck Jones Road. More investigation is needed to determine the cause of the collision or contributing factors.
Note that there is a high volume of cycling activity in Cary. I believe that this amounts to over one million miles per year of bicycle travel on Cary roadways. According to a transportation consultant who worked on the town's comprehensive transportation plan, about 80% of cycling transportation miles in Cary are traveled by "avid" road cyclists who operate on roadways in the correct direction of travel for vehicular traffic. The vast majority of "non-avid" cycling transprotation miles are also traveled in the correct direction for vehicular traffic and most also occur on the roadway.
Given that wrong-way bicycle travel represents a very small percentage of the total number of bicycling miles, but represents about one half of the collisions, I believe that this breakdown of collisions illustrates the very high danger of wrong-way bicycle travel. Anyone traveling contra-flow on a vehicle, especially one capable of greater than walking speed, should be very cautious before moving in front of cross-street and driveway traffic. Operators of such vehicles should attempt to travel with the ordinary flow of vehicle traffic whenever possible. In general, the safest way to operate a vehicle in an urban area is according to the rules that apply to drivers of vehicles. Such operation maximizes one's visibility and predictability to other road users.
Regards,
Steven Goodridge
North Carolina Coalition for Bicycle Driving
http://humantransport.org/bicycledriving/