Road Safety: Rider Visibility in Daylight Conditions

Roman Beck and Jim Harris

Cycling at night in California requires the use of a white light visible from at least 300 feet in front. While this safety equipment is not required for riding during daylight, cyclists can increase their safety by using a flashing white front light and red rear light during daylight conditions, especially during early morning and late afternoon hours. The purpose of the lights is to make the cyclist visible to others, rather than to make the roadway visible to the cyclist.

Many cyclists wear bright-colored clothing to increase their visibility at all hours, but often this is insufficient in certain daylight conditions. Over the past ten years, the County of San Diego has averaged about eleven fatalities in nearly 1,200 cycling collisions per year. Many of these collisions occurred as a result of motorists’ claims that the cyclist was not visible.

The background against which an object is viewed plays an important role. The more complex the background, the greater the importance of the bicyclist’s clothing. The ideal clothing will have both light and dark components, as well as a pattern making the bicyclist recognizable. Anything that can be done to make drivers "think bicycle," thereby raising bicycle expectations and raising bicycle rider position on their priority list, may significantly enhance the bicyclist’s safety.

Sometimes collisions occur due to an incorrect perception of closure speed. In the case of left turns in the face of oncoming traffic, the driver may conclude, in error, that there is sufficient time to complete the turn. Distance judgments are generally based on the angular size of the approaching traffic and a driver’s assessment of the rate of increase in angular size of the object. The small physical dimension of the bicycle rider means that the capability for making accurate judgments of bicycle closure will be severely limited. The brighter you are, the better your chances.

When planning your next ride, think carefully about how visible you will be to drivers, especially if you could be out during early morning or late afternoon hours. The right clothing and the use of lights could mean the difference in making that ride just a pleasant memory.

From Chain Guard Volume 19, Number 1, Page 6, January-February 2005