Another important pre-trip check should be exterior and interior lighting. Vehicle check lanes revealed an overall failure rate of over 25 percent in the lighting category. The Car Care Council reminds motorists to check their lights monthly. Other suggestions from the Council include turning on headlights both day and night. This helps define your car's position on the road, and its distance from other drivers. When your vehicle's lighting is defective, other motorists may not get the message that you intend to stop or turn. The end result could be disastrous.