Bicycle safety is just one of the many areas where the Trek Bicycle Corporation strives to stand out. From the top down, the company is committed to remaining at the vanguard of bicycle visibility and safety. Its UCI WorldTour team Trek-Segafredo is due to unveil a special fluorescent training kit for its riders, and the company looks for new ways to improve cyclists’ visibility at all levels. Interestingly the journey took Trek far from its home in Waterloo, Wisconsin, when they joined South Carolina’s Clemson University in a longterm joint venture with the school’s Human Factors Psychology program. PELOTON sat down with Darlene Edewaard, a Ph.D. student at Clemson, who has spent the last four summers applying her research to products that can actually increase cyclists’ safety.
PELOTON Magazine: Darlene, explain to us how a Ph.D. student in human factors psychology came to work with Trek/Bontrager?
Darlene Edewaard: Human factors psychology is also known as engineering psychology. Basically, we study how humans interact withtechnology, and then we work to make devices, systems and interfaces that are safe and user-friendly. Here at Trek/Bontrager I am a safety researcher studying how drivers interact with cyclists. At my lab down in Clemson University, I specialize in vision science, and I apply knowledge of vision science to transportation safety. My area of expertise comes into play here because I research ways to make vulnerable road users, such as cyclists, more conspicuous to approaching drivers from safe distances so that drivers can avoid future collisions.
PELOTON: And are you a cyclist yourself?
Edewaard: Yes I am, although I am primarily a runner.
PELOTON: And what attracted you to working with Trek/Bontrager?
Edewaard: My first year at Clemson, Trek contacted my lab, because we focus on transportation safety, and they wanted us to conduct studies to find ways to make bicyclists safer. And for me as a doctoral student it was the perfect project to focus on—I love that my research is practically applied to physical products that serve the purpose of trying to save lives. So for the past four summers I have come to Waterloo, where we are studying ways to help drivers see cyclists from farther away by enhancing their conspicuity with apparel and lights.
PELOTON: And what are some of the things that you are discovering?
Edewaard: Using lights on bikes, both during the day and at night, can enhance the conspicuity of cyclists as well as wearing bright clothing during the daytime and retro-reflective clothing [that sends light back to its origin] at night. These conspicuity aids help drivers see cyclists from farther distances and help them recognize that they are looking at a cyclist and not an ambiguous object.
PELOTON: What are some of the biggest challenges that you face in your research and study?
Edewaard: The weather can pose a challenge for my research—the weather and lighting conditions need to be consistent across experimental sessions, which is when we run participants, when we conduct research outside. The amount of people required to carry out open-road experiments can also be a challenge—it usually takes a team of four or five researchers to run a single experimental session, and we usually run one or two participants during one experimental session. So, as you can imagine, it takes a lot of time and planning to collect all of the data for the studies conducted with my lab in Clemson.
When I first arrived at Trek, I conducted an extensive literature review of all the previously published bicyclist-conspicuity studies with one of my lab partners from Clemson. The major takeaway from the lit review was that there were not a lot of studies out there that assessed bicyclist conspicuity, especially regarding daytime conspicuity, and many of the studies were done outside of the U.S. The whole transportation-safety realm is a pretty big field but studies in pedestrian conspicuity far outnumber studies on cyclist conspicuity. This opened up a huge opportunity to conduct research, and since then we have been tackling as many research questions as we can, regarding bicyclist’s safety.
PELOTON: What are some of the exact tests that you have been doing?
Edewaard: In one test that we are doing we install a sonar sensor onto a bike, which projects a beam of sound waves that humans can’t hear. But when something goes in front of the sensor, the sound waves bounce back to the sensor and the sensor picks up the distance from the object to the sensor. In our study, we examine how far away cars are from cyclists when they maneuver around a cyclist. More specifically, we are assessing whether different lights and apparel affect the amount of distance that drivers give cyclists as they maneuver around cyclists.
We are also conducting studies to assess ways in which taillights can be used to enhance a bicyclist’s conspicuity—specifically help drivers recognize that a bicyclist is present in the roadway. With apparel, we are looking at the effects of brightly colored clothing on cyclist conspicuity during the daytime and what areas of the body to put brightly colored material on for the best results. And we do the same thing with retro-reflective material at night. We are also looking into helmets to see if the application of different colors, retro-reflective material or lights can help a driver see a cyclist from farther away.
PELOTON: Obviously this is an ongoing study, but what are some things that you have discovered so far?
Edewaard: We have seen, for example, that while it is always better to ride a bike with lights than without, flashing lights are better able to enhance conspicuity in both daytime and nighttime. Another thing that we have found is that if you take the lights that are normally mounted on the seat post of the bike and put one on each of the rider’s shoes, the lights will highlight the rider’s movement, especially when used at night, and help drivers identify the cyclist from much farther away than when flashing seat-post lights are used. This is because we as human beings are perceptually sensitive to recognizing movement of other human beings. It’s a perceptual phenomenon called biomotion, and our brains are hardwired to perceive biomotion. Therefore, conspicuity aids, such as lights and apparel that highlight the movement of the rider help drivers to recognize the presence of bicyclists from greater distances.
Some of our studies also serve to dispel certain myths. One study that we discovered in the initial literature review, for example, showed that cyclists can overestimate their own visibility by up to 700 percent. The distance between a vehicle and a cyclist who is wearing a fluorescent vest, when the cyclist is instructed to estimate the distance from which the driver would be able to detect his or her presence, can be seven times greater than the actual distance from which a driver can see that cyclist at night. So we are looking into ways to bridge such gaps in understanding.
Cyclists tend to think that wearing brightly colored clothing both day and night will help their conspicuity. But while it helps in the daytime, bright clothing worn at night will not enhance a cyclist’s conspicuity because human eyes can’t see color in the low-light conditions at night. Cyclists should use lights or retro-reflective material while riding at night.
PELOTON: What are the specific areas where there is the most room for advance and improvement?
Edewaard: A cyclist’s conspicuity in the daytime is wide open for research and development, because there still have not been many studies conducted during the daytime. More accidents actually happen during the daytime because, well, more people are riding then. So daytime safety is a crucial area to be studied.
We also spend a lot of time working with conspicuity rather than visibility. Conspicuity can be defined as “how noticeable an object is among its surroundings,” whereas visibility is defined as “whether an object can simply be seen.” To provide an example of both, if you go into a parking lot full of white cars and one red car during the daytime, all the white cars are visible, but none are necessarily conspicuous. But the one red car in that parking lot will be conspicuous among all of the white cars. Conspicuity is important for grabbing an observer’s attention.
Drivers have a lot to attend to while they are driving, and human attention is limited. Cyclists need to do everything possible to enhance their conspicuity to capture the attention of drivers.
PELOTON: A lot of people that ride during the day are simply commuting to work; they may have a dress code of some kind or simply do not want to wear very brightly colored clothing. Are there ways to work around such constraints, ways perhaps to work conspicuity into daily wear?
Edewaard: The easiest thing anyone can do is to buy a USB rechargeable set of bike lights. They are easy to put on and take off a bike and recharge. Using flashing lights is an effective, unobtrusive way to enhance conspicuity. Cyclists can also get brightly colored and retro-reflective bands to put around their ankles while riding during the daytime and nighttime respectively. All of these options do not alter one’s attire.
PELOTON: What is the most satisfying thing for you as a Ph.D. student to be working with Trek/Bontrager?
Edewaard: Being in academia, we publish our studies in journals and often only people in our field read those studies. But with Trek, they are taking what we are doing and actually applying it to products. My lab is getting to see our work applied in a manner that can save lives. And being as that Trek is a very large and influential company, they have the power to spread the word about the results of our research and educate riders on how to stay safe while riding. That’s all very exciting! It’s really rewarding and not an opportunity that a lot of researchers get.