How Do Bumper Cars Work?

If you’ve been to an amusement park in your lifetime, then you’ve probably driven or rode in bumper cars. These boisterous bumping buggies are some of the most fun you can have for cheap at a fair, but have you ever stopped and wondered how they work?

Often referred to as dodgems, bumping cars, or dashing cars, bumper cars take on one of three main designs when it comes to their functionality with the roots dating back to the late 1920s.

The oldest and most common method for giving bumper cars their juice lies in using a conductive floor and ceiling, with reverse polarity. Contacts on the bottom of these cars touch the floor while the long rod in back touches the ceiling completing the bumper car’s circuit. An example of which looks a little like this:

Some newer cars use a method of alternating strips across the floor separated by spacers of insulative material. This design eliminates the ceiling grid and the alternating strips supply the current. The bumper cars in this design need to be large enough to cover at least two strips at any one time to complete a circuit. The cars will have an array of metal brushes on the bottom that can make contact with the conductive strips.

The key to making this design work is alternating the polarity of the conductive strips so that there is always a completed circuit in the car. When the circuits are completed, a motor will push the car in whatever direction the steering wheel directs.

These two electrified floor-ceiling and electrified floor designs are what you typically will see in amusement parks. They usually run on a range of 12 to 48 Volts at around 200W and have a variety of safety factors in place to avoid any mishaps. With this relatively low voltage and a generally high amperage, riders are mostly safe from electrical mishaps between contacts, not to mention operators closely monitor the power supply, shutting it off when riders exit vehicles.

Some bumper car facilities use cars that run on batteries. Aboard the Quantum-class cruise ships by Royal Caribean, their bumper cars do just that.

This design avoids the conductive floor and ceiling design mainly so that the space can be easily converted to multipurpose space. Square footage is obviously valuable on cruise ships, so Royal Caribean made sure that the massive amount of space taken up by the bumper car arena can be used for other purposes. The downside to this design is simply that the cars need to be charged for long periods of time.

These three designs encompass the power aspect of bumper cars, but there’s a little more engineering required when it comes down to making this carnival ride work.

Arena floors are usually sprinkled with graphite to help decrease friction. This helps the wheels of the car move the car efficiently while overcoming the friction between the brushes or contacts between the floors and ceiling.

Around each vehicle, there is a large rubber bumper which functions as a cushion to both protect the car and the rider from damage or injury. Part of why we get so much enjoyment from bumper cars is because it gives us a controllable boost of adrenaline from the shock of being physically jolted. Drivers experience a change in their motion and become aware of their inertia. For anyone that paid attention in high-school physics, you’ll also note that riders with different masses will have different effects from a collision. If the largest rider runs into the smallest rider at full speed, the smaller rider is going to be in a world of hurt. On the other hand, there’s little that the small rider can do to shock the larger rider with the same force short of traveling at a greater speed, which is usually limited by the arena or the car circuit.

Cars are usually steered with a steering wheel that spins a complete 360 degrees allowing for the cars to also move in reverse with just a turn of the wheel. Usually, cars will also have an accelerator handle or pedal that controls the flow of current to the electric motors which move the car.

All this engineering behind bumper cars makes for an intensely fun ride and possibly a painful one if you’d like your back to stay in alignment. So, through a careful combination of mechanical and electrical engineering that dates to the late 1920s, we now enjoy riding bumper cars at carnivals across the country.