ebay 808 keychain HD cameras less than $30
will do the job I have 2 but I prefer the go pro cameras their almost bombproof will last a long time great mounting options/support more professional etc but again you get what you pay for its your choice
keychain cameras or dashboard cameras are common in some parts of europe and asia they use them to record while driving to have video proof when someone is at fault
i don't know if you saw recent news footage of Russian Aircraft that crashed recently in russia and parts of the aircraft went flying into the highway and an automobile with a camera captured the crash when it happened.