Incidentally, another challenge is audio quality. Wind noise can overwhelm everything else. I've noticed some cyclists will call out the license numbers and descriptions of offending vehicles, so there's a backup in case the video isn't clear.

It may also be essential to record clear audio in case the impact or assault comes from off camera. If the camera is mounted on the bike but the bike isn't facing toward the vehicle or a person who assaults the cyclist, clear audio may be the only record.

I've rigged up homebrewed wind screens for my various cameras. A Velcro type tape on the camera body over the mic input helps -- 3M Command is good, secure and easily detachable. I cut thin strips of the 3M Command tape and surround the mic port with the strips -- it's essential to avoid covering the mic with the 3M Command tape because the soft foam substrate will mute the sound completely.

Then I'll use the soft cloth loop section of Velcro clothing tape over the mic. This is the stuff that needs to be sewn on, no adhesive. It's okay to cover the mic with the soft cloth Velcro loop tape. It's almost completely transparent to audio. Does a good job at blocking most wind noise, and is lower profile than most wind screens.

However this hasn't worked out as well with the Ion Speed Pro mic when mounted on my helmet. It does work with the camera mounted on the handlebar. My best guess is the helmet's vents are kicking up too much air turbulence. So far the only solution I've found that reduces wind noise on the helmet is to wrap the entire barrel body of the Speed Pro in Glad wrap! Even then it still picks up some wind noise. It might work better with a mountain bike helmet or commuter helmet, the types with fewer and smaller vents.