Car vs. bicycle accidents happen for a variety of reasons, but one of the most common is simple: The driver of the car looked right at the bicycle, did not see it or did not realize what it was fast enough, and hit it.
It sounds astounding, but consider the small size of a bike compared to pickups, SUVs, semi-trucks and even passenger cars. It's easy for them to blend right in, especially when there is a lot of visual clutter.
Plus, drivers are used to looking for cars. They're focused on other vehicles. Many look right past a bike without registering what they're looking at because they're actually staring at cars around and behind the bike.
Nine different studies were carried out to see if the colors that cyclists chose to wear had any impact on these cases. In eight of the nine reports, researchers said that fluorescent colors offered the greatest protection. The best colors were red, orange and yellow.
A big part of the reason is contrast. Roads are gray and black, as are many vehicles. A cyclist on a black bike wearing a gray hoodie is going to blend right in, while a cyclist on an orange bike wearing a red hoodie and a yellow helmet will stand out against all of the other visual stimuli.
Of course, though it's wise for cyclists to think about what they wear and how they can stay safe, they don't have an obligation to protect themselves. Drivers must see them and drive safely around them. No matter what a cyclist is wearing, if he or she is hit and injured, that cyclist may be able to seek financial compensation.
Source: Cycling Tips, "Does reflective and fluorescent clothing make us safer?," Matt de Neef, accessed Sep. 18, 2017