Trucks don’t have third brake lights, and that’s a pretty big safety issue. Those sets of three red lights at the top are kind of like one, but they’re always illuminated. Every red light on the back of semis and box trucks is always lit up. Sure, they get brighter under braking, but that’s not enough; that’s the entire reason the third brake light exists. So... Maybe, just maybe, we’d have less deaths from this:

... if we just slapped another light on the back of every truck and made sure it lights up only under braking.