How to Care for and Use Your Vehicle's Safety Equipment

For you to survive in today's driving environment, the safety equipment installed in your vehicle will play a large role. No matter how well you drive, you are not safe unless your vehicle is in good condition. If it is not, you could have a serious crash.

What safety equipment is required and what is its proper function?


Operating a vehicle with just one tire under-inflated can reduce the life of the tire and increase fuel consumption. With the high cost of fuel alone, proper tire inflation is an important consideration. In cold weather, temperatures decrease the air pressure in tires, which adds to rolling resistance, especially in snow. It is most important to check tire pressure regularly (at least monthly), especially after a sharp drop in temperature. Tire pressure can drop about one PSI for every ten degree (10oC) drop in temperature. If you find your tire pressure has dropped, inflate it to the correct pressure as soon as possible. The tire pressure that is indicated on the tire itself is the maximum pressure for the tire itself and may not be applicable to your vehicle. Check your vehicle's owner's manual for the manufacturer's recommended pressure.

Rotating your tires can help decrease premature tread wear as well as improve fuel economy. Most vehicle tires should be rotated about twice a year. Your vehicle owner's manual will supply you with the recommended rotation pattern and frequency for your particular vehicle.

Periodically inspect your tires for any cuts or abnormalities, such as bubbles or excessive wear. Your vehicle's tires should be kept with at least 1/16th of an inch tread of tire. Bald or unevenly worn tires will reduce or eliminate any control you would have over your vehicle in an emergency situation.

Lighting Equipment:

Your vehicle is equipped with headlights, taillights, brake lights, daytime running lights, turn signals, license plate lights, reflectors, and parking lights. Every vehicle must have two headlights — one on each side on the front — and a beam indicator showing when the high headlight beam is on.

Headlights should be used between sunset and sunrise; and at any other time when visibility is reduced to 500 feet, such as at twilight or during inclement weather. (Twilight is considered the time between sunset and full night or between full night and sunrise.) Headlights are required in inclement weather such as rain, fog and snow, and whenever your windshield wipers are in use.

Headlights require very little maintenance — mostly they just need to be kept clean. However, they should be inspected for any breaks or cracks in the glass and, of course, checked to make sure no bulbs are burnt out and that they are illuminating correctly.

Headlights can be shone in either the high beam or low beam mode. When driving at night, avoid looking directly into the headlights of approaching vehicles as you may become temporarily blinded while driving. You should shift your eyes down to the lower right side of your traffic lane.

Standard low beam headlights are typically used in areas of traffic where the intense light of high beam headlights would be blinding or would be an irritant to other drivers. Low beams are typically used during twilight hours as evening approaches when the light of day is beginning to darken, throughout the nighttime, and in the early morning hours when the light of day is just beginning to brighten, or during fog, rain, sleet, snow, smoke, dust, or any such conditions when visibility is reduced. Be sure to use only low beam headlights in snow or fog to eliminate reflecting the light back into the driver's eyes. Under normal conditions, your headlights let you see only about 350 feet ahead.

High beams are typically used sporadically and only for temporary additional lighting when needed. High beam headlights should be dimmed on lighted roads and before coming within 500 feet of oncoming vehicles.

The two tail lights on your vehicle are typically designed to send out light that is visible for a distance of 500 feet to the rear of the vehicle.

All vehicles must be equipped with two brake lights (stop lights) except that models manufactured prior to model year 1960 are required to have only one brake light.

Daytime running lights are generally used as a visual aid for oncoming traffic. They produce a lower light than standard headlights but provide added visibility of oncoming vehicles.

Backup lights are white lights at the rear of the vehicle that tell other drivers you are backing up.

Turn signals are a major means of communication between drivers. If you don't know what the driver ahead of you is planning to do, you cannot adjust accordingly. How many times have you been driving and the person in front you suddenly, without warning, slows down to turn? If that driver had warned you of his/her intention to slow down and effectuate a controlled turn, you could've adjusted your speed accordingly and thereby warned those vehicles behind you as well.

Turn signals should always be used in the planning stage — when you are planning to:

  • Change lanes (at least 3–4 seconds before changing, depending upon speed*);
  • Enter a highway or roadway;
  • Exit a highway or roadway; and
  • Turn (100 feet in advance)

*If the speed limit is more than 35 MPH, signal at least 100 feet before you reach the turning point. For speeds less than 35 MPH, signal at least 50 feet in advance.

Once your maneuver has been successfuly completed, make sure your signal turns off. Most signals turn off automatically; however, if the steering wheel has not been turned sufficiently enough to allow the devices that control the turn signal to return to their original positions, you will have to manually turn off the signal. A continuously blinking turn signal only serves to confuse other drivers.

If you are planning to turn directly after going through an intersection, do not turn on your signals before the intersection. Wait until you reach the intersection. If you turn on your signal before reaching the intersection, other drivers will think that you are planning to turn at the intersection and they might try to go around you and pull in front of you.

Vehicles must also be equipped with a white light that illuminates the vehicle's rear license plate when the headlights (or auxiliary lamps) are lighted. Vehicles must be equipped with two red reflectors, one on each side of the vehicle. These reflectors must be placed at a height of 15 to 60 inches and be visible up to 600 feet. (Reflectors must only be visible up to 350 feet on vehicles manufactured prior to model year 1960.)

Vehicles must also be equipped with parking lights that must be either white or amber on the front, red to the rear. Parking lights may be installed in combination with other lights.


Every motor vehicle must have two braking systems — a standard brake and a parking brake — in case of the failure of one. The standard foot pedal brake on your passenger vehicle should be able to stop the vehicle traveling 20 mph within a distance of 25 feet when upon dry asphalt or concrete pavement surface free from loose material where the grade does not exceed one percent. Large combination trucks typically require at least 50 feet of stopping distance when braked from the same speed! The parking brake should be adequate to stop and hold the vehicle.

In order to maintain vehicle control, a properly maintained braking system must be in place that does not exhibit a tendency toward premature or individual wheel lock-up. Modern braking systems may include a system identified as ABS, for Anti-lock Braking System. ABS enables the driver to maintain steering control during hard braking by limiting or even preventing wheel lock-up.

Anti-lock brakes do not help a driver stop any faster; they allow the driver to maintain steering control to avoid going into a skid. With a standard braking system (not ABS) in an emergency, it was common for a driver to pump the vehicle's brakes to avoid locking up the wheels and skidding. ABS was devised so that in an emergency the driver can apply the brakes hard, maintain consistent pressure and still retain steering control.

However, ABS should not be relied on under all conditions. There are certain road conditions that will cause the ABS to react unexpectedly. Gravel roads, snow-covered roads, even rainy conditions can reduce ABS effectiveness. Drivers should have at least a basic understanding of the systems that allow their vehicles to operate properly, be mindful of road conditions, and drive at reasonable and safe speeds.


Your vehicle must have a horn which can be heard from a distance of 200 feet. Drivers should be aware that horns are put on as standard equipment in motor vehicles. A horn should be used in an emergency situation dictated by a driver's own discretion. Proper use of the horn is a helpful technique in defensive driving as it warns other drivers of road conditions and hazards that may affect them. When passing other vehicles, the horn may be used to alert other drivers. Often times, use of the horn can warn opposing drivers of impending danger or lane straddling, allowing them to make the necessary adjustment to their driving. A properly functioning vehicle horn is typically audible from a distance of 200 feet.


In order to help reduce air pollution, vehicles must be equipped with a muffler and exhaust system. All models beginning with model year 1968 must be equipped with an exhaust emission system.


On your vehicle, the inside (rearview mirror) and outside mirrors (side view mirrors) should be adjusted to reflect a view of the highway for a distance of at least 200 feet behind your vehicle.


The windshield of your motor vehicle has to be made out of safety glazed glass that meets all federal standards on safety glass. All replacements of glass for any car must be with safety glass. You are also required to have your windshield wipers in good working order. If the front windshield is dirty, it will be difficult to see the road ahead. The windshield must allow seventy percent light transmittance.

License Plates:

All passenger and commercial vehicles must have two valid license plates. One must be displayed at the front and the other must be displayed at the rear. Dealer plates and those commercial vehicles that are only issued one license plate are exempted.

Fuel Cap:

The vehicle's fuel cap must be checked to determine if the fuel cap is missing or is defective on any vehicles from 2 to 24 years old. Exceptions are antique vehicles, circus vehicles, slow moving vehicles, motorcycles, and vehicles operated exclusively by a fuel other than gasoline and vehicles newer than 2 years or older than 24 years.

What equipment is considered unsafe and therefore is not allowed?

In direct conflict with the safety equipment that is required for vehicles, there is some specific equipment that is considered unsafe and is therefore not allowed, such as the following:

  • A red light showing from the front (except on emergency vehicles);
  • A bell, siren, or exhaust whistle (except on emergency vehicles);
  • A muffler cut-out;
  • Anything that extends more than three inches beyond the left side or six inches beyond the right side of the body, running board, or fenders of the vehicle; and
  • Flashing red lights on the front (except emergency vehicles, school buses, and church buses)

Persons are also prohibited from modifying or weighting vehicles in such a manner that the body of the vehicle is below the lowest part of the rims of the wheels. Driving Safety Articles:
This article was written by defensive driving staff writers and reviewed for accuracy by defensive driving instructors. All articles are based on current traffic laws and defensive driving practices. This article is intended for educational purposes only, and should not be taken as legal advice or literal interpretation of any specific traffic law.