A speed bump is a raised ridge built into a road or parking lot that forces drivers to slow down. When a car drives over a speed bump too fast, everyone inside feels an uncomfortable jolt. Drive slowly, and you barely notice it.

Speed bumps appear in places where safety matters more than speed: school zones, hospital parking lots, residential neighborhoods where kids play. They work through simple physics. A driver could ignore a sign that says “Slow Down,” but nobody wants the jarring thump of hitting a speed bump at full speed. The bump itself enforces the speed limit.

People also use “speed bump” to describe any small obstacle that slows progress toward a goal. If you're working on a science project and discover you need a material the teacher doesn't have, that's a speed bump. It's not a disaster that stops you completely, just an annoyance that requires slowing down and finding another route. Unlike a roadblock, which completely halts progress, a speed bump means you need to adjust your approach and keep going.