“In a world addicted to speed, I blur the moments into one unholy smear. ... When I fully enter time’s swift current, enter into the current moment with the weight of all my attention, I slow the torrent with the weight of me all here.” ― Ann Voskamp, One Thousand Gifts: A Dare to Live Fully Right Where You Are
Resting the camera on the dashboard of the car to keep it relatively stable would be a good approach. Then it's just the car's movement and the cars outside that will create the blur and not camera shake. This will have to be experimental as far as shutter speeds and exposure are concerned. Obviously night time would work best if I am going to record light streaks. The camera pointing at back seat and kids with blur outside?