Learning The External Features of Your Car for The Driving TestUpdated Dec. 25, 2020
Let’s begin our introduction to the controls and physical components of your vehicle by looking at the car’s external features. Next time you are parked up safely and away from other traffic, take a 360-degree walk-around the outside of the vehicle to see if you can identify each of the features listed below.
Your vehicle’s tires are made of rubber, fabric, wire and a few chemical compounds. The main ring-shaped body of the tire holds compressed air to provide a malleable, shock-absorbing cushion which will deform and reshape as it rolls over the surface of the road. Raised ridges of rubber known as “tread” line the outer surface of the tire. Most standard passenger vehicles have symmetrical tread (a repeating pattern of grooves and raised ridges), though different types of tread are available on tires designed for high-performance or bad driving conditions.
The weight of the vehicle presses the surface of the tire against the roadway, helping the tread to grip the road and create traction. The energy created in the engine is transferred to the wheels, through the tires and onto the surface of the road as the car moves. The connection between the tires and the road determines how well your vehicle can accelerate, brake and change direction. Tires must be properly aligned, inflated to the car manufacturer’s recommended pressure and well-maintained, for the vehicle to speed up, slow down and maneuver safely.
The center or “hub” of your vehicle’s tires should be covered with hub caps. These circular disks are typically made of plastic or rubber and can be snapped into place easily by hand. Most people assume that hub caps are purely decorative but like the other external vehicle components discussed in this section, they serve an important purpose. Hub caps help to keep the car’s wheels in good condition, by blocking dirt, rocks and other debris from the roadway which may otherwise enter the hub of the wheel and cause damage. Hub caps are generally quite long-lasting, though you should check them regularly to ensure they have not been damaged and are still affording the wheel decent protection.
Move around to the back of the vehicle, shift your gaze up slightly, and you should be able to see the exhaust pipe protruding from beneath the rear bumper. The exhaust pipe is the only visible part of your vehicle’s exhaust system, which is designed to remove dangerous waste gases and fumes produced as the engine burns fuel. In most vehicles, the exhaust pipe is made from steel, stainless steel or aluminum.
Never stand close behind a vehicle while the engine is running or leave a vehicle’s engine running in an enclosed space. Breathing in carbon monoxide and other exhaust fumes from the vehicle’s engine is very harmful to your health and can be deadly.
Your vehicle’s rectangular license plate is printed with a unique combination of letters and/or numbers, which is registered with the department of motor vehicles under your name. It may also have symbols or initials linked to your state of residence. License plate numbers help law enforcement agencies to solve vehicle-related crimes and return recovered stolen vehicles to their rightful owners.
Every state uses a slightly different format for registration numbers, though all require drivers to have at least one license plate on display, just above the rear bumper of the vehicle. More than half of all states also require drivers to display a license plate on the front of the vehicle, so if you live in one of these regions – you should have a license plate there too!
You have a legal responsibility to keep your license plates clean enough to be read at a distance. If you fail to do this, you may be stopped and cited by a police officer. If your license plates are lost, stolen or damaged to the point that they are unreadable, you must contact the DMV to request a replacement set.
Your vehicle has two taillights on either side of the rear of the vehicle. With the exception of turn indicators on certain vehicles, all rear-facing lights on road vehicles are red. This means that all road users know they are looking at the rear-end of a vehicle when the body of the car is not visible due to darkness or poor conditions, but they see red lights.
The taillights are programmed to light up automatically whenever your vehicle’s headlights are on, or the parking brake is active. On most vehicles, the taillights share a globe with the brake lights (meaning that they are housed next to each other, under the same casing). In other vehicles, the brake lights may be positioned higher up on the back of the car.
The vehicle’s brake lights will either be immediately next to the taillights or positioned separately, higher up on the frame. Many modern vehicles have a brake light stripe running down either side of the rear window, as this is thought to increase visibility for road users following at a distance, whose view may be restricted by other traffic. Brake lights will activate automatically whenever the driver applies pressure to the brake pedal, to warn motorists to the rear that the vehicle is slowing down or stopping. Like tail lights, brake lights are red. However, they are always of a more luminescent red than the taillights, so that other drivers can tell the difference.
Turn indicator lights are located on the left and right of the vehicle, close to the headlights and taillights. When you activate your turn signal inside the vehicle, the corresponding indicator lights outside the vehicle will begin to flash. This communicates your intention to turn, merge or change lanes to other road users nearby.
Front-facing turn signals are nearly always amber-colored, whereas rear-facing turn signals may be red or amber. The United States is the only western country that does not have amber rear turn signals as a legal requirement, though this may change in the future. According to the National Highway Traffic Safety Administration (NHTSA) amber turn signals are up to 28% more effective than red rear-facing signals when it comes to avoiding collisions. They estimate that cars with amber turn signals at the rear are 5.3% less likely to be rear-ended than similar vehicles with red rear-facing lights.
All front-facing lights – not including turn indicators – must be white or pale yellow. This means that during low visibility conditions, road users can tell whether another vehicle on the roadway is traveling towards them or away from them. The car’s headlights are positioned on either side of the front of the car, usually just beneath the curve of the hood. Your headlights must be activated using a switch inside the vehicle, during low visibility conditions, at night and when driving on mountain roads in some states.
All vehicle headlights have two settings: low-beam and high-beam. High-beam lights are very bright and must only be activated when you are not driving in the immediate vicinity of any other road users. Whenever a vehicle approaches you from the opposite direction, or you approach another vehicle in the same lane from behind, you must switch to the less-dazzling low-beam lights. Most modern vehicles use a single bulb capable of emitting different levels of light for both low-beam and high-beam settings.
Parking lights are positioned on the front and rear of the vehicle, near the headlights and taillights. Their purpose is to warn other road users of your presence while you are parking the vehicle. Some modern vehicles may also have daytime-running LED lights alongside the taillights and headlights, to increase visibility during daylight hours. Front parking lights are white or amber, while rear parking lights are red.
While the fuel tank is quite obviously inside the vehicle, the access cap for the tank will be located on the side or rear of the car. Every time you wish to top up the fuel tank with gas, you will need to find and open the fuel tank access door. Often, the switch to release the fuel tank door is somewhere inside the vehicle near the driver’s seat.
If you are driving an older vehicle, you will probably find a plastic fuel tank cap behind the access door. To refuel the vehicle, unscrew this cap and insert the gas pump nozzle into the hole it reveals. Don’t forget to screw the cap back on and close the door when you’re done! Many modern vehicles have capless fuel tanks, which are designed to be more convenient and secure. If this is the case in your vehicle, you will see a round valve rather than a plastic cap. To top up the tank, simply insert the gas pump nozzle directly into this valve.
Side-view mirrors are mounted on the forward side of the vehicle’s driver and front-passenger doors. Their purpose is to help the driver scan the roadway to the rear-side and rear of the vehicle. Whenever you merge, turn, change lanes or alter lane position, you will check your side-mirrors for conflicting traffic before completing the maneuver. The position of these mirrors can be adjusted to afford the driver the best possible view of the road. This is usually done manually in older vehicles and electronically in newer vehicles.
According to NHTSA federal safety standards, all side mirrors must provide 1:1 reflection that is undistorted. In simple terms, they must reflect images exactly as they are. As side mirrors are relatively small compared to the vehicle, this can somewhat limit the driver’s field of vision. So, most modern vehicles also include a convex or aspheric plate on the side mirror, separated from the main flat mirror. This smaller section of the mirror will allow the driver to see greater distances but will make objects appear further away than they really are.
Your windshield is designed to provide a clear view of the roadway to the front of the vehicle, from the driver’s seat. It also serves as a barrier to prevent dirt and debris from the roadway from entering the vehicle. Modern windshields are made of laminated safety glass, to protect vehicle occupants in the event of a collision or an object striking the windshield. Unlike ordinary glass, safety glass will break into small cubes of glass rather than glass shards, if it is shattered. It is your responsibility as a driver to keep your windshield clean. Allowing dirt, mud, snow or residue of any kind to build upon the windshield will interfere with your view of the road and is a citable offense in many states.
At the base of the windshield, you will see folded windshield wipers. Their purpose is to remove dirt and moisture from the windshield to keep your view of the road clear. Windshield wipers are comprised of two plastic arms that pivot at the base to move side to side across the windshield. The flat surface of each arm has a rubber “blade” that cleans the windshield as it slides across the surface of the glass.
Windshield wipers are motorized and are activated by the driver using controls inside the vehicle. Typical windshield wipers can be set to several different speeds, depending on the amount of dirt or rain which needs to be wiped from the windshield. In extremely heavy rain, you would probably need to set the wipers on their highest speed to maintain a decent view of the road. When the windshield is dirty, you use a button inside the vehicle to squirt the screenwash onto the glass. This will help the wipers to clear the dirt rather than smearing it across the windshield.
You can expect to see the features discussed in this module on all road vehicles, as they are legally required for a car to be considered “road-worthy”. It is possible that your car has additional non-standard features that are not included here. If so, you will be able to find information about their purpose and operation in your vehicle owner’s manual.
Note that as the vehicle owner, you are responsible for ensuring the external features of your car remain in good condition. Your lights and license plate must be clean, and your tires should be replaced regularly, as the tread wears down to an unsafe level. In most states, law enforcement officers have the power to issue you a ticket for dirty or inactive lights, unsafe tires or an unreadable license plate. Where lights and tires are concerned, not keeping on top of maintenance would also render your vehicle less safe to drive.
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