In researching the Chappaquiddick tragedy, I noted 3 things that seem rather sinister:
1) Ted Kennedy had a driver, yet took his keys to his car from the driver and went driving with Mary Jo Kopechne!
2) The day before the accident, he went for a swim in that same area where he went off the bridge...
3) No autopsy was ever performed on Mary Jo Kopechne!
Most stem from a perception that the younger kennedy brother was given preferential treatment.
Most folks could draw the conclusion that the Senator was taking the young lady out to a secluded location. The turnoff would have been hard to find at night, but the senator's visit the previous day would have brought it to mind. Possibly he was thinking of a romantic moment parked on the bridge. We will never know.
A good study on this incident is Senatorial Privilege: The Chappaquiddick Cover-up by Damore, Leo (1989). New York: Dell Publishing.
For more general study visit Wikipedia - Wikipedia Reference on Chappaquiddick
I *believe* the car was crushed the next day as well.