If we were to tell you that you alone could prevent a traffic pileup, you would probably think we were making things up. After all, we usually think of traffic as the cost of commuting, occurring due to an accident or some magical force of nature. And yet, we’ve all been there. Our GPS tells us that there’s a slowdown up ahead, and while we expect to see a multi-car collision as the reason for the slow down, it turns out that there’s nothing there!
So, how do pile-ups occur? It turns out that traffic behaves much like waves. When traffic is flowing smoothly, one wave follows to the next at regular intervals, and cars keep a constant speed. However, the second that one of these waves slows down, the distance between that wave and the one behind it becomes smaller.
So, getting back to cars. When a car suddenly slows down, due to a pothole, accident, or more commonly someone changing lanes or checking their phone, the car behind them has to slow down, and so does the car behind that car and so on.
As you can see in the animation above, a traffic jam occurs because the second car does not have enough room to match the speed of the cars in front after a change in speed.
So, how does one prevent a traffic jam? The answer is simple, but is one that goes against our natural driving instincts. The three simple rules for avoiding and preventing traffic jams are:
- Maintain ample distance
- Maintain constant speed
- Don’t change lanes abruptly
Maintain ample distance
The only way to actually stop a traffic jam from growing is to maintain significant distance between your car and the car in front. This gives you the opportunity to slow down with time if you see a traffic wave forming in front of you, and gradually allows you to reduce your speed without reaching a full stop. However, there are some drawbacks to this method, since other cars will likely want you to speed up to reduce the distance between you and the car ahead, or will likely cut in front of you, reducing the space between you and the car ahead of you.
Maintain constant speed
Another important tip to keep in mind is to maintain a constant speed. This may be difficult to do when you see the car in front of you speeding up, but if the car in front of you is tailgating, then a pileup is likely to occur whenever they press their breaks. Therefore, even though it might be tempting to speed up when there’s space ahead, remember to maintain a constant speed and only increase your speed gradually.
Don’t change lanes abruptly
And lastly, one of the main causes of pile-ups is someone changing lanes abruptly, so do your best to avoid doing so. When a car changes lanes abruptly, this forces the cars behind you to brake suddenly, causing a pileup. In addition, you may find yourself having to brake abruptly in order to match the speed of the cars above, in particular when merging into a slower lane.
If we can all follow these three simple rules, traffic can flow more smoothly and we can all get to our destinations safely and without the frustration of sitting in an unnecessary traffic jam.
By the way, one of the touted benefits of autonomous vehicles are the expected reductions in traffic pile-ups. Since all the self-driving cars would be communicating and able to make split-second decisions, they will be able to follow one another closely and maintain constant speed. The fly in the ointment is when you add a human driver into the system and nobody can predict what they are going to do.
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