The Physics of Speeding Show Why It’s So Dangerous




driving at night on a highway with people in the car, seen through the glass roof

driving at night on a highway with people in the car, seen through the glass roof


Speeding is one of the most frequent causes of automobile accidents, and it’s also one of the main reasons people get tickets while they’re on the roadway. Speeding when you’re behind the wheel is incredibly dangerous, so why do people continue to do it? 

There are different reasons ranging from not paying attention to a fast-paced lifestyle in which people often feel like they’re in a hurry to get everywhere. 

Understanding the mechanics of excessive speed may help reduce your tendency to go too fast when you’re behind the wheel and give you a greater understanding of exactly why it’s so risky. 

The Physics of Speed

Speed, if you’re going to look at it in physics terms, is a measure of the distance traveled per unit of time. 

In simpler terms, it’s how fast an object moves. 

Speed doesn’t account for factors like direction, while velocity does. 

The Faster Something’s Going, The Harder It Hits

If you’re tempted to go even a little above the speed limit, you may think it’s no big deal, but is that the case? Not necessarily.

Speed is dangerous because of physics. The faster something is going, the harder it’s going to hit. That means the faster you’re going, the more likely it is that someone will be injured, and the more likely it is that the injury will be serious. According to research from Australia, a pedestrian has a 20% chance of dying if they are hit at 50 km per hour. That’s around 31 MPH. 

The risk of dying triples if they’re hit at 80 km per hour, which is just under 50 MPH.

If a pedestrian is struck by a vehicle traveling at 50 MPH, they have almost no chance of surviving the collision. 

Vehicles are designed to absorb some of the energy that comes with an impact that occurs when you’re speeding, and the associated decrease in speed, but your body isn’t. 

The same research from Australia regarding the above effects of speed shows that if you were to reduce your speed by as little as 5%, you could reduce deadly collisions by 30%. 

Something else to note is that the faster a vehicle is going, the shorter the amount of time the driver has to stop in order to avoid a collision. 

Reaction Time

As was touched on, reaction time plays a role in the physics of speed and the dangers it can create. 

If a car is traveling around 5 MPH faster than another car that is of equal size and braking ability, the car traveling faster is going to have traveled quite a bit more than the slower car, which is important even if the reaction time is the same between both drivers. 

The braking distance is the distance a vehicle travels before it stops when the brakes are hit. The braking distance is affected by not only speed but also the slope of the road. 

If you’re going uphill, you’re going to be able to stop more quickly because of the effects of gravity.

There is also an impact of frictional resistance between your car’s tires and the road. If you have new tires and are driving on a dry road, you’re going to be able to stop more quickly than a vehicle with worn-out tires that’s on a wet road. 

Understanding the Risks of Speeding

Beyond the physics, it’s so important to have a real understanding of the risks of speeding. According to the National Highway Traffic Safety Administration (NHTSA), speeding has been involved in around one-third of all vehicle fatalities for more than two decades. In 2017, it was a contributor to 26% of all traffic-related fatalities.

When you are speeding, it means there is a greater likelihood you will lose control of the vehicle, and it reduces how effective the protection equipment in your vehicle is. 

It requires an increased stopping distance, and when you’re speeding, as was touched on, the injuries from a traffic accident are more likely to be severe. 

What if you aren’t speeding, but someone on the road is?

First and foremost, if you are in the left lane and someone is trying to pass you, get over and let them.

If you see a speeding vehicle, try and stay as far away as possible, because someone speeding is more likely to lose control, and if someone is behaving aggressively on the roadway, don’t try to speed to keep up in any way. 

It should be noted that if you add distracted driving as a factor paired with speeding, the results are likely to be even more disastrous on the roadways. 


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