Heat lead
Someone who is traveling at a higher rate of velocity than you on the road, making speeding less dangerous as they will be more likely to get caught.
"Dude, you're going 20 over, aren't you worried you'll get laser radar'd?"
"No way man, that white skyline up ahead is doing at least 30 over, he's my heat lead."
"No way man, that white skyline up ahead is doing at least 30 over, he's my heat lead."