The idea is to make roads that don’t invite speeding. So instead of wide straight roads you narrow them and add curves and speed bumps. Putting a 25 MPH sign on a road that can easily be driven at 50 MPH is a pipe dream. People don’t drive by looking at their speedometer they go the speed that they can travel comfortably. Car design keeps improving so the ride is smooth so bad driving is encouraged. Think of a grocery store parking lot. Cars and people everywhere right? Yes. But are people seriously injured or killed in grocery store parking lots? No not really. But cross the street in front of your house and you’re putting your like in jeopardy to a 1500 pound mass of metal traveling 40 miles per hour with a distracted parent in a rush behind the wheel. Make driving difficult = fewer severe accidents.