If you want to play the scenario with the same vehicle again(the last random vehicle), turn ON the headlights(Dpad up or keyboard 'N') before restarting the scenario.
Turn OFF the headlights when you want to randomize the vehicle again.

Platinum: 0:38
Gold: 0:45
Silver: 0:55
Bronze: 1:00

Tips:
Use the steering for in air control
Don't go on the throttle as soon as the car lands; Allow the vehicle to settle down