What Causes Car Accidents?

What Causes Car Accidents?

The dictionary defines accident as "an unexpected and undesirable event, a mishap unforeseen and without apparent cause." Strictly speaking, most accidents are not accidents at all: they are collisions that could and should have been avoided. So, what causes them, and how can you avoid them?

Four factors contribute to the vast majority of collisions. In ascending order they are:

Equipment Failure

Roadway Design

Poor Roadway Maintenance

Driver Behavior

Over 95% of motor vehicle accidents (MVAs, in the USA, or Road Traffic Accidents, RTAs, in Europe) involve some degree of driver behavior combined with one of the other three factors. Drivers always try to blame road conditions, equipment failure, or other drivers for those accidents. When the facts are truthfully presented, however, the behavior of the implicated driver is usually the primary cause. Most are caused by excessive speed or aggressive driver behavior.

Equipment Failure - Manufacturers are required by law to design and engineer cars that meet a minimum safety standard. Computers, combined with companies' extensive research and development, have produced safe vehicles that are easy and safe to drive. The most cited types of equipment failure are loss of brakes, tire blowouts or tread separation, and steering/suspension failure. With the exception of the recent rash of Firestone light-truck tire failures, combined totals for all reported equipment failure accounts for less than 5% of all motor vehicle accidents.

Brakes - Modern dual-circuit brake systems have made total brake failure an unlikely event. If one side of the circuit fails, the other side is usually sufficient to stop a vehicle. Disc brakes, found on the front wheels of virtually every modern vehicle, are significantly more effective than the older drum braking systems, which can fade when hot. ABS (Anti Blockier System) or anti-lock brakes prevent the wheels from locking up during emergency braking maneuvers, allowing modern vehicles to avoid many accidents that previously would have occurred.

Tires - Today's radial tires are significantly safer than the bias-ply tires of 25 years ago. They still, however, need attention regularly. Under inflation, the most frequent cause of tire failure is considered the main culprit in the recent Firestone tire-failure fatalities. Uneven or worn-out tires are the next most serious problem and can also lead to tire failure. Uneven wear is caused by improperly balanced tires, or misaligned or broken suspensions. Remember, all that keeps you connected to the roadway is your tires. If you don't check your own, have your mechanic check them every 5,000 miles.

Steering & Suspension - Your suspension keeps your tires in contact with the roadway in a stable and predictable manner. Your steering enables you to go around road obstacles and avoid potential accidents. Even a safe, well-trained driver is helpless in the event of a steering or suspension system failure. Such failures are catastrophic, especially at high speeds. Have your suspension and steering systems checked out by a mechanic every 10,000 miles.

With regular component inspections by trained individuals, equipment failures can be virtually eliminated.

Roadway Design - Motorists may blame roadway design for accidents, but it's rarely the cause. Consultants such as the Texas Transportation Institute have spent years getting road barriers, utility poles, railroad crossings, and guardrails to their current high level of safety. Civil engineers, local governments, and law enforcement agencies all contribute to the design of safe road layouts and traffic management systems. State and federal governments provide guidelines to their construction, with design flexibility to suit local conditions. Roadways are designed by engineers with special consideration given to the following:

Hazard Visibility - Permanent roadway hazards consist of intersections, merging lanes, bends, crests, school zones, and livestock or pedestrian crossings. Temporary hazards include road construction, parked or disabled vehicles, accidents, traffic jams, and wild animals (especially deer).

Roadway Surfaces - Engineers can use different surfaces (for example, grooved pavement) depending on the environment, traffic speed, traffic volume, and location of the roadway (noise barriers). Roadway markings let drivers know about their ability to pass safely (dotted & double lines), the location of the roadway in inclement weather (reflective cats-eyes & stakes), and where road surface ends and the shoulder begins.

Traffic Control Devices - Traffic light signals, speed limit signs, yield and stop signs, school & pedestrian crossings, turning lanes, police surveillance cameras, and traffic circles or roundabouts.

Behavioral Control Devices - Built-in obstacles that limit the ability of a vehicle to travel, including crash barrels, speed bumps, pedestrian islands, raised medians, high curbing, guard rails, and concrete barriers.

Traffic Flow - Interstate highways remain the safest roads because their flow of traffic is in one direction. One-way streets ease traffic congestion in city centers as well. Rural two-lane roadways are statistically the most dangerous because of a high incidence of deadly head-on collisions and the difficulty impatient drivers' face while overtaking slower vehicles.

Roadway Identification Signs - enable someone without a detailed map to travel from one place to another. They give advance notice of intersections, destinations, hazards, route numbers, mileage estimates, street names, and points of interest.

Weather - inclement conditions can aggravate existing hazards and sometimes create new road surfaces (ice & snow).

Poor Maintenance - Roadway maintenance contributes to some motor vehicle accidents, but not to the extent that drivers use it as an excuse. Unfortunately maintenance schedules and procedures vary greatly from city to city and state to state, so nationwide standards don't exist. Below we outline some potential roadway maintenance shortcomings that you should be aware of.

Debris on the roadway can be a problem, and is the responsibility of local highway departments.

Faded road signs, and signs obscured by foliage, occasionally contribute to accidents. If you know of any offending signs, contact your local police department to see if they can get the