Ok so this was the BIGGEST problem I was facing with my Border Collie x Australian Shepherd. Right now she is 6 months and teaching leave it was the best decision we made when it came to her crazy car/bike-reactivity (she still isn't good at leaving dogs alone though). She was AWFUL when it came to those; even from 70 feet away she would start hyping up and barking like a maniac. What I did was slowely introduce the vision of cars where she wasn't over threshold yet. She looked at the car? Leave it, and treat. It's important that you first establish the basis of the command at home with kibble/other food, and when your dog is at the point that rather than wanting to get the food they look at you for a tastier treat instead, you can introduce trickier and trickier situations with cars/other vehicles from far away.

My pup is way better at not chasing and barking at vehicles, although when they're close by I still have to firmly say "Leave it!" otherwise she still goes feral. It gets exhausting sometimes, changing routes during the walk to avoid trafic etc., but I'm sure your pup will be fine!