A study carried out by Bath and Brunel Universities looked at how much space drivers give when overtaking. The researchers wanted to see if the clothing cyclists wear will affect drivers’ behavior. Different clothing was chosen to indicate different levels of experience. The extreme of inexperience was indicated by a cyclist wearing an outfit including a high visibility vest with the words, “Novice Cyclists, Pass Slowly”. At the other extreme the cyclist wore a racer outfit. A vest was also worn with the words, “Police Witness.com Move Over Camera Cyclist”.
Previous research is cited showing that drivers seem to have significantly reduced the room they give cyclists overtaking. The mean distance has decreased from about 1.8m in 1979 to about 1.2m in 2014. It is also interesting that drivers pass much closer in the morning than in the evening with the distance increasing linearly throughout the day.
A single male cyclist rode a consistent route for a number of months wearing each of the outfits. The route was the cyclist’s usual commute into West London, involving a wide range of different riding conditions over 26 km. Instruments were used to measure and log the proximity of each vehicle which passed. An ultrasonic sensor was used which has an accuracy of 1 cm and samples at 10 Hz. Data logging was carried out using an Arduino Uno. Plans for the replication of the test equipment are available from the authors Ian Walker, Ian Garrard and Felicity Jowitt.
Surprisingly there was no statistically significant difference in the mean passing distance for the novice or the racer. Drivers gave the same distance to an apparently experienced cyclist as they would to a novice.
There was, however, a small but significantly increased distance when the cyclist wore a vest indicating that the police were involved and they were being filmed.
Full details of the paper: The influence of a bicycle commuter’s appearance on drivers’ overtaking proximities: An on-road test of bicyclist stereotypes, high-visibility clothing and safety aids in the United Kingdom, Walker Garrard Jowitt, Accident analysis and prevention. , 2014, Vol.64, p.69-77