If a person appears 20 meters from my hood while I'm on the interstate, they're toast, whether I'm going 100 km/h or 150. Surely the unpredictable can happen at any moment with other cars, but I find follow distance more important than speed. If you're bumper to bumper at 100 km/h, you're going to have a worse time than if you give 10 cars space at 150 km/h.