Engine Breaking in the Snow

As we have gotten closer to winter break we have been receiving more and more snow. This unfortunately has been making road conditions worse and worse. Hopeful, by the end of the semester the weather will settle down a little bit and road conditions will clear up, but in case they don't I though I would offer some advice for driving in the snow to all of those who will be driving home for the holidays.

One of the biggest issues with driving on snow and especially on ice is the decreased friction that your tires will get with the road. This can make breaking extremely difficult and has led to a lot of accidents. However, one trick that can be used to help stop yourself when you are driving on roads that are in poor condition is what is known as engine breaking. Engine breaking is a term used to describe the action of slowing down a manual car by downshifting to a lower gear. This works because the lower gear increases the number of revolutions the engine needs to make in order to create the same amount of angular displacement in the wheels of the car.

This technique works due to the fact that when not pushing on the gas pedal the main thing that keeps the engine of a car spinning is the kinetic energy that is transferred from the wheels of the car to the engine. This can be modeled by the following equations:

Since the kinetic energy of the system remains the same and the kinetic energy is equal to the rotational kinetic energy plus the linear kinetic energy, as one type of kinetic energy decreases the other must increase to compensate. By downshifting we are increasing the angular velocity of our engine which in turn reduces the linear velocity of the car.

Performing an engine break can take some practice as doing one incorrectly could damage the engine and transmission of your car, but when performed correctly can be an indispensable tool for making quick stops on slippery surfaces while driving.