Driving Too Slow Can Be More Dangerous Than Speeding Traffic studies show that vehicles moving 10 mph slower than surrounding traffic are up to six times more likely to be involved in an accident. The danger isn’t just speed—it’s speed difference. Slow-moving vehicles disrupt traffic flow, increase sudden braking, and create unexpected obstacles, especially on highways. Important Details: • 10 mph slower greatly increases crash risk • Speed difference is key danger factor • Causes sudden braking