You cannot exit a police car by yourself when you sit in the back as young Will did.
When Will reverses out of the gas station parking lot in pursuit of Jonas, the right indicator light of his car is not working and you can see an emblem on the grill of his car. In the next shot of the chase, the emblem is gone, and both lights are working.
In the flashback showing the childhood of the police officer you see his father with a modern radio set.