We’ve all been there: traffic grinds to a halt and you inch along expecting to see an incident or broken down car, but then everyone gets back up to speed with no apparent reason for the slow down. It turns out that there is a good reason and it can all be explained through science.
It comes down to drivers’ inability to hold a consistent speed or distance from the car in front. Essentially people travel at different speeds, then slow down a bit too much when they catch up with another car. The car behind them then slows down a bit more, and the car behind them a bit more, and so on. Eventually, thanks to the fact we can’t just hold it steady and impatient drivers can’t resist tailgating, we end up with pointless jams. That’s why smart motorways are being introduced to manage traffic flow better.