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January 09, 2018

Study puts a number on bicyclists' road compliance

Bicyclists and motorists comply at similar rates, study finds

Transportation Bicycling
Carroll - Cycling in Center City Thom Carroll/PhillyVoice

A cyclist rides west on JFK Boulevard in Center City Philadelphia, Nov. 2, 2016.

A recent study has injected some real data into the seemingly endless grumbling between bicyclists and motorists.

Cyclists comply with general traffic rules about 88 percent of the time, according to a pilot study commissioned by the Florida Department of Transportation.

The study monitored 100 bicyclists in the Tampa Bay region who agreed to attach a bicycle data acquisition system to their bikes. Using cameras, sensors and GPS devices, the systems captured both front and rear video recordings, acceleration speeds, gyroscope data and location information.

The study, conducted by the Center for Urban Transportation Research at the University of South Florida, asked bicyclists to complete a questionnaire following each trip. In all, researchers detailed more than 2,000 hours of bicycle rides.

And they found that bicyclists and motorists adhere to the rules of the road at about the same rate.

Bicyclists recorded an 88.1 percent compliance rate during daytime travel. At night, that rate dipped to 87.5 percent.

By comparison, motorists had an 85.8 percent compliance rate during the daytime – based solely on information recorded by the bicycle data acquisition systems. Researchers deemed they did not have enough data to determine a compliance rate for nighttime drivers.

Cyclists were more conservative at night, staying in their right-of-way and in safe locations, according to the study. During the day, they tended to violate pedestrian signals if they had good visibility and clear distance from potential collisions.

Cyclists often maintained the same speed when crossing an intersection, instead of slowing down and proceeding with caution, the study found.

The youngest cyclists, ages 18 to 25, took significantly more risks than older bicyclists. They also were more likely to be distracted.

Only one bicycle crash was recorded during the study – a motorist struck a cyclist from behind as the cyclist waited to turn left. Researchers blamed the crash on insufficient bicycling infrastructure – there was no bike lane – and a driver violating right-of-way rules.


The study captured 22 "close calls," including 19 involving passing vehicles and another three involving motorists making a turn. A minimum of three feet between the passing vehicle and bicyclist was used to determine "close calls."

Among the "close calls" involving passing motorists, only five occurred when a bike lane was present. One of those happened when a bicyclist chose to ride in the traffic lane despite an available bike lane.

The study concluded that a lack of dedicated bike lanes and sidewalks is "a primary reason" for close calls, because cyclists and motorists must share limited road space. Therefore, researchers found "sufficient bicycle lane width is beneficial for reducing the risk of close calls with passing vehicles."

Philadelphia boasts about 200 miles of bike lanes, though another study deemed Philly the ninth-most dangerous U.S. city for bicyclists.

At least three bicyclists died last year, according to the Bicycle Coalition of Greater Philadelphia. Four died in 2016 while seven others died in 2015.

Cycling advocates have called on the city to increase the number of protected bike lanes – those that place physical barriers, such as delineator posts, between cyclists and motorists. Those calls intensified after two bicyclists were struck late last year while riding along unprotected bike lanes.

The city current has less than three miles of protected bike lanes, but Mayor Jim Kenney has pledged to install 30 more miles of the lanes during his time in office.

The city's first protected bike lane opened in September 2016 along a one-mile stretch of Ryan Avenue in the Mayfair section of Northeast Philadelphia. Another protected bike lane – running from 45th to 34th streets along Chestnut Street – was completed in late August.

The city is adding a protected bike lane stretching seven blocks near the South Street Bridge.