• Try making your own CineSaddle® out of a small nylon gymbag filled with beanbag chair innards (small styrofoam pellets) and strap it down with love and care.
• Use a polarizer on the lens.
• If the speed and traffic conditions are not too dangerous, mount a large flag above windshield to reduce glare and reflections.
• Control start/stop (and possibly a few other camera functions) with remote.