I don't think it's 'resurfaced', unless you have found something new (source?). It's never gone away and won't as long as there are people who refuse to see the obvious re this tragedy and who live for 'conspiracies'. Apart from the fact that I think Diana was an accident waiting, Dodi's father had a lot of enemies, many of whom just might have been after him, rarther than Diana - if you want a conspiracy?
I have to say I find it odd, assuming the car was fitted with back-seat belts, that Diana wasn't wearing one which she appeared to always do. Other than that, unless the driver wanted to commit suicide, why would he crash the car, UNLESS he was drunk and on drugs, and speeding.
Other car? Weren't there any number of cars likely to have been on the road/tunnel at that time of night?