According to the National Highway Traffic Safety Administration, almost 20% of all car crashes and 12% of near-misses are caused by either driver exhaustion or flat-out falling asleep behind the wheel. This accounts for nearly 100,000 deaths or injuries each year. In 2009, over 33,000 people were fatally injured in car accidents.

While driver drowsiness is just one factor in accidents, manufacturers are rapidly engineering a wide range of advanced safety systems into their vehicles. Some of these are available only on high-end cars, but as with safety features of the past many will eventually become mainstream in price and availability - if not required as standard equipment on passenger cars and light trucks.

While these systems can certainly help prevent accidents, in all likelihood they may simply be reinforcing what the driver already knows. No amount of technology can replace safe driving behavior and a good dose of common sense with a side serving of appropriate judgment. According to NHTSA, almost 95% of all accidents are a result of human error. In other words, these systems won’t necessarily save us from ourselves.

Here is a run-down of some of these advancements:

A new smartphone app, Anti Sleep Pilot, helps you calculate your fatigue levels and either assists in keeping you awake or recommends that you pull over to rest.

Active head restraints move forward and up in a rear-end collision to reduce neck injury.

Adaptive cruise control uses radar to regulate the distance between you and the vehicle in front of you - taking driver judgment out of the equation. In some instances this is combined with other collision mitigation systems.

Adaptive headlights tilt and swivel based on driving and weather conditions (when cornering, for example).

Lane departure warning systems alert you through vibration or audible warnings when sensors determine you may be drifting out of your lane.

Breathalyzer ignition locks require you to blow into a tube before your vehicle will start.

Drowsy alert systems use a combination of driver and vehicle metrics to determine if you may need to pull over and rest, alerting you to the condition.

Smart seatbelt systems adjust tension and position accordingly in anticipation of an impending collision.

Telematics systems, such as OnStar, can send 9-1-1 emergency assistance after an accident even if you cannot make the call yourself.

Blind spot monitoring systems use radar or laser technology to warn you if a pending lane change is unsafe.

Collision mitigation technology responds to an imminent accident by adjusting seatbelt and seating positions, applying the brakes, rolling up the windows, closing the sunroof, etc. How much is controlled by the system depends on the vehicle and manufacturer.