What you need to do is create a variable for throttle in your vehicle BP, and expose it to Matinee(a tick box in the variables details) Plug that variable to Set Throttle Input node, and execute Set Throttle Input with Event Tick. Now place that vehicle into your map, call it in Matinee and you’ll see that throttle variable when you use a Float Property Track. You can do the same thing for steering as well and control the vehicle’s speed and direction according to your cinematic sequence.
Needless to say this is only useful for simple cinematic stuff. It would be better to use actual vehicle AI for a car chase or racing sequence, etc.