Why motorists slam their horns...
... as a bike commuter for 10 years, mostly in Chicago, and recently in the NW suburbs, I am amazed still at how motorists think it is okay to slam their horns when passing cyclist.
Given, I try to be as visible as I can- light colored clothing, reflective vest, reflective commuting bag, blinking taillight, reflective tape and bike reflectors, headlight.
Also, I always wear a helmet, signal early and often with my arms and hands, check behind me and ride close to the shoulder as much as I am able. But still, on two occasions, I have had motorists lay on their horns this week. It makes me nuts!
Anyway, at 5:00am today, given it was a bit foggy out, I was midway through my ride and I could see the headlights of a vehicle from behind... I continued cautiously, but confidently riding, and as the pickup truck passed, the driver decided to lay on their horn... No, I didn't crash, but was quite irritated as my blood pressure spiked for a moment... What happened on your commute today?