How Vehicle Speed Specifically Changes Braking Distance
Last reviewed: 2026 · Driviology Road Safety Education Team
Quick Answer
Vehicle speed changes braking distance exponentially rather than linearly - doubling your speed can quadruple your braking distance - which is why MTO recommends a minimum two-second following distance that doubles in adverse conditions.
Our overview of factors affecting braking distance mentions speed briefly; this page drills into exactly how much it matters.
Thinking Distance Plus Braking Distance
Total stopping distance is made up of the distance travelled during reaction time plus the distance needed to physically stop once the brakes are applied - both of which grow with speed.
Why the Relationship Is Exponential
Doubling your speed from 30 km/h to 60 km/h does not just double your braking distance - it roughly quadruples it, making even small speed increases significant.
Why the Two-Second Rule Accounts for This
MTO’s recommended minimum two-second following distance, doubled in adverse conditions, is designed specifically to build in enough margin for this exponential relationship.