Previous research on bike lighting
In most states, bike lighting is required when riding during the nighttime. The qualms that come with nighttime riding are well documented. Daytime accidents as a whole are more likely than nighttime accidents. Something is needed to decrease the chances of this occurring. According to a study by Madsen et al bicycle riders are 19% less likely to have an accident with daytime running lights than someone without lights. Drivers look but fail to see cyclists leading to potential driver-cyclist conflicts.
During the daytime, there are many distractions (increased number of cars, pedestrians, etc.) within the environment that can divert a motorist’s attention. If a cyclist isn’t wearing fluorescent or visible clothing it can decrease the likelihood of the sight of the cyclist even further. This article review is going to focus on the effects of the visibility of cyclists who are utilizing bike lighting during the daytime.
Study Design
Introduction
The Conspicuity Benefits of Bicycle Taillights in Daylight1 was a research effort completed by Darlene E. Edward, et. al. The authors wanted to prove that daytime taillights can increase visibility for bicyclists. Therefore enhancing the safety of cyclists who share the road with motor vehicles. The authors of this study first wanted to differentiate between the words detection and recognition. Detection is when the motorist first detects an object and recognizes the object as a bicycle.
The design
Ninety undergraduate college students were selected for this study. Everyone one of the participants was to have 20/40 or better vision as well as a log contrast sensitivity of 1.65 or better. By the time they narrowed down the participants, there were only 35 participants who took part in the study. Participants provided informed consent.
Each participant was tasked with viewing 25 video clips of a vehicle’s forward view of the road. Of the 25 videos, only 5 were analyzed. The subjects were not aware of what videos were being analyzed. The remaining 20 videos were just distractor videos that contained extraneous bicyclists or pedestrians. The distance that separated the camera vehicle from the test bicyclists and the pressed button indicating that they saw the cyclist was measured.
All in all, there were 5 lighting conditions.
- A control condition where the cyclist in the video had a single taillight but it wasn’t turned on.
- The flashing light on a seat post where there was an irregular flashing light with an irregular flashing pattern.
- A steady light on a seat-post where the light had 25 lumens of brightness but it was a steady light.
- Then there was the heel condition. In this condition, two lights were mounted to the subject’s heels.
- Finally, the warping triangle included three taillights in total. A single taillight at 25 lumens (steady) mounted on the seat post, and two taillights at 25 lumens (steady) on the heels of the cyclist’s shoes.
Procedure
Subjects were tasked with viewing the 25 videos one by one. The participants were positioned in the chinrest and went through a 5-point calibration procedure. They were given an eye tracker and were asked to “search for any persons on the road” (e.g. cyclists, walkers, or runners). They were informed that not every video would contain a person. If they saw someone in the video then they had to press the space bar on the computer. The process was repeated for 25 videos which were randomized for all the participants. The procedure took 30 minutes to complete.
Limitations
Researchers felt as though further studies into the correct amount of light that should be emitted from the heel lights are needed to further enhance this study.
Research results
The results were in the author’s favor. The recognition distance (in order from longest to shortest) was the flashing seat post, then the steady seat post, the heels, the warping triangle, and the control condition. Basically flashing lights proved to be the most efficacious.
The researchers found it peculiar that the heel light condition was less than the steady light condition. Due to the fact that humans are more perceptually sensitive to the movement patterns of other human beings. They attributed this to the fact that the lights were pointed away from the camera, therefore, obscuring the view of the lights on the heels.
Some of the recommendations that they had was an educational program for the bicyclist community on the best methods to increase visibility to drivers while riding during the daytime.
Cycling 4 Safety’s Take
This is a great study for riders who complete many of their miles during the daytime. The results showed that flashing lights are more recognizable than other modes of lighting. Researchers noted that more studies are needed in order to make a firm recommendation for flashing lights over the other methods but the results from this study are promising.
One of the main reasons people do not ride bikes is the feeling of not being safe. Cyclists don’t know whether the other motorists can see them or not. Having the results from a reputable university can only solidify the bicyclist’s confidence in bike lighting. Now you are equipped with the knowledge to be seen more clearly during the daytime.
- Edewaard, D. , Szubski, E. , Tyrrell, R. & Duchowski, A. (2019) “The Conspicuity Benefits of Bicycle Taillights in Daylight”, Driving Assessment Conference. 10(2019). doi: https://doi.org/10.17077/drivingassessment.1720