There is one study that shows that car drivers give less space to cyclists who look more "professional"/well-equipped than those who look like casual riders. O

There is one study that shows that car drivers give less space to cyclists who look more "professional"/well-equipped than those who look like casual riders. Of course people who cite this research say that the solution is to not wear a helmet, as opposed to take measures to make drivers give you more space when you wear a helmet. In my case, I have an old large Coca-cola plastic crate on my rear rack, plastered with reflector stickers, and that seems to give me plenty of space. A female friend holds her U-lock in her left hand and that seems to do the trick as well.