Why does Tallahassee from Zombieland always put a three on his cars?

Me and my friend are watching Zombieland and wondering why he puts a three on all of his vehicles.Why does Tallahassee from Zombieland always put a three on his cars?
Honestly, I have no idea. My guess is that's how old his son was when he died?Why does Tallahassee from Zombieland always put a three on his cars?
He's a fan of racecar driver Dale Earnhardt #3