Negligence is careless conduct that ends up causing harm to another person. In a car accident scenario, a person can be negligent by doing something that he or she should not have done (for example, running a red light or speeding), or by failing to do something that he or she should have done (for example, failing to yield, not stopping for a pedestrian, or forgetting to turn on headlights while driving at night).

Here's another way of thinking about negligence: A driver must use reasonable care to avoid injuring other motorists, passengers, or pedestrians. If a driver is not reasonably careful, and someone is harmed as a result, the driver (and the driver's car insurance carrier) can be financially liable for that person's injuries and other losses (damages).

The law requires drivers to use reasonable care to avoid harming anyone else on the road. But what exactly does this entail? Let's look at some examples.

Driving at a reasonable speed . Drivers have a duty to drive at a reasonable, prudent speed in light of the existing traffic, road, visibility, and weather conditions. Even driving at the speed limit can be considered negligent if, for example, visibility is low, the weather is bad, or the circumstances warrant particular caution (driving by a school where you can expect children to be crossing, for example).

Vigilance and keeping a proper lookout. Drivers have a duty to be alert and to maintain a careful lookout for other vehicles, pedestrians, and road hazards. Drivers are expected to see the things that an ordinary, prudent person would see. Failure to do so can constitute negligence.

Maintaining control of the car. Drivers are expected to keep their vehicle under control at all times. Negligence may be inferred if a car loses control (by overturning or leaving the roadway) for any reason.

Maintenance and proper use of vehicle equipment. Drivers are expected to maintain their vehicles in safe working order. For example, lights and brakes should be working properly.

Driver Duties Imposed by State Law

Each state's motor vehicle laws govern how drivers are expected to behave on the road. In certain circumstances, violating a motor vehicle law gives rise to a "presumption" of negligence—meaning that the defendant must present evidence to prove that he or she was not negligent.

Examples of conduct that may give rise to a presumption of negligence include:

•        driving under the influence of drugs or alcohol

•        violating right-of-way rules, including a pedestrian's right of way, and

•        driving on the wrong side of the road.