i had 150km drive on a stretcher inthe back of an ambulance.
i left at 4cm and was full dilated 30 mins from the hospital.
i was told to not push until we got there.

it was terrible! couldnt move, no DH to support me no pain relief

When i went into labour with #2 - i refused to get in the car when the labour progressed very quickly (2 hr labour like #1)... as i wasnt doing the car trip again.

Instead gave birth with DH on the bedroom floor with ambos .

xx00
Only advice i can give is when the first contraction hits - dont listen to them if they send you home (like me) and get there asap.
established labour and crowning in a vehicle is not fun.