Reducing road speeds is logical, says Newsroom, because most of our roads are designed to prioritise the mobility of vehicles over access and safety, allowing cars to move along the street far too fast. Speed limits are historically set using the 85% rule, which determines a road’s speed based on how fast the fastest 15% of people drive on the road. The amazing thing about reducing traffic speed is that small changes can have a massive impact on safety. Reducing speeds from 50kmh to 30kmh (a 40% reduction) reduces the likelihood of a collision between a car and person being fatal from 80% to just 10%.