Why does braking distance quadruple when speed doubles?

Vehicle Stopping Distance Calculator - Speed, Reaction & Braking

Calculate total motor vehicle stopping distance including driver perception-reaction distance and physical braking distance across dry, wet, and icy asphalt roads.

⚙️ Configuration & Inputs

Vehicle Driving Speed (mph) Highway speed

Driver Reaction Time (seconds) AASHTO highway standard: 1.5 seconds

Road Surface & Weather Condition

📊 Results & Analysis

Total Stopping Distance 331.3 ft (101.0 m) Approx. 22 car lengths

Perception-Reaction Distance 143.0 ft (43.6 m) Distance traveled before foot hits brake

Physical Braking Distance 188.3 ft (57.4 m) Tire friction deceleration

Speed in Feet per Second 95.3 ft/sec 104.6 km/h

Physics of Vehicle Stopping Distance

Total stopping distance is the sum of reaction distance and braking distance:

Total Distance = (Speed × Reaction Time) + (Speed² / (2 × g × μ))

Frequently Asked Questions

Kinetic energy is proportional to velocity squared (E = ½mv²). Doubling your speed from 30 mph to 60 mph multiplies kinetic energy by 4, requiring four times as much friction work to stop.