Incidentally, if you enjoy experimenting with video to document your rides and have a little extra money to play with, try an older generation (2012 era) Nikon J1, J2, S1 or similar entry level Nikon 1 System camera.

These featured the CX or one-inch sensor, also used by Sony and Samsung. That's an old video TV tube descriptor -- the sensors aren't physically one-inch in width, height or diagonally, but are larger than the teensy sensors used on most smart phones, action/traffic cams and entry level P&S digicams. The slightly larger sensor will give an edge in resolution of fine detail and low light performance with less noise at high ISOs.

The kit zooms may jiggle too much and eventually be damaged from road vibration, but the fixed focal length 10mm f/2.8 Nikkor would be ideal for a traffic camera. This is equivalent to a 28mm wide angle on a 35mm film camera or full frame digital camera.

If I'm recalling correctly the early Nikon 1 System cameras had 10 mp still resolution, 1080p at 30 fps and 720 at 60 fps. That's what my V1 has, which is spec'd a bit higher than the J1 and S1.

I used my V1 several times to record video from my bike in 1080 and 720, and the quality was much better than the Ion Speed Pro, especially in dim light. It recorded license numbers more reliably.

However it is relatively bulky and heavy, making it a challenge to mount securely. I used a stout nylon mini-tripod and ballhead, bolted to a metal base and lashed to the handlebar or head tube with tape, Velcro strips and zip ties. Not elegant but it worked. The Nikon V1 had the option of taking still photos without interrupting the video (in 1080 or 720 format, rather than the standard 3:2 aspect ratio). The simple, uncluttered top plate featured only the large shutter release button, video on/off button, and small, recessed on/off button. Easy to operate while cycling in full auto program mode.

I've also considering trying an Olympus Tough Cam. These are weatherproof, shock proof, with internal zooms that move very little. They're expensive compared with the cheaper knockoff action and dashboard cams, but possibly more versatile for some bicycling uses, especially if you enjoy taking snapshots along the ride.