There is something to be said about getting your kid a car they like and are proud of and thus protect it along with themselves. Giving them an ugly old beater sort of incentivizes beating it to pieces and taking risks. Letting them drive your beloved truck doesn't instill pride in ownership either.

Best dad move I ever heard on this subject was a guy got his son a Volkswagen van with basically all the parts in crates. He had his son put it together and helped him over summer break. When his son turned 16 he had a nice van for banging girls and treated it like his baby.