Stopping distance is the sum of reaction distance (speed multiplied by reaction time) and braking distance (velocity squared divided by twice the gravitational acceleration times friction coefficient). Road grade, vehicle weight, and tire condition also affect the final number.
- Reaction distance at 60 mph with 1.5s reaction time is 132 feet
- Braking distance at 60 mph on dry pavement is approximately 172 feet
- Total stopping distance at 60 mph on dry road is about 304 feet or 20 car lengths
- Doubling speed quadruples braking distance due to v² relationship
| Speed | Reaction Dist. | Braking Dist. | Total |
|---|---|---|---|
| 30 mph | 66 ft | 43 ft | 109 ft |
| 45 mph | 99 ft | 96 ft | 195 ft |
| 60 mph | 132 ft | 172 ft | 304 ft |
| 75 mph | 165 ft | 269 ft | 434 ft |