Crash tests are conducted under laboratory conditions by car safety research organisations to measure how well a car’s structural design and safety systems work to protect its occupants in an accident.

In the United States, crash tests are carried out by the National Highway Traffic Safety Administration (NHTSA), a branch of the Transport Department, and the Insurance Institute for Highway Safety (IIHS), a safety-research group sponsored by the insurance industry. In Europe, they are done by the European New Car Assessment Programme (Euro NCAP).

NHTSA

The NHTSA NCAP or New Car Assessment Programme provides consumers with vehicle safety information such as front- and side-crash ratings, and more recently, rollover ratings, to help consumers with their vehicle-purchasing decisions. It uses a star rating system of one to five stars, with five being the highest score.

NCAP was initiated in 1978 with the main purpose of measuring the relative safety potential of vehicles in frontal crashes. Side-crash ratings were added starting with model-year 1997 vehicles. Rollover ratings were introduced starting with vehicles made in 2001.

Every year the agency chooses new vehicles which are predicted to have high sales volume, those that have been redesigned with structural changes, or those with improved safety equipment to test.

In the future, test results will be supplemented by a rating to indicate if advanced safety technologies such as electronic stability control and lane departure warning systems, are in place.

Even though a vehicle may not have been rated under the NCAP, all vehicles sold in the United States must be certified by the manufacturer as complying with national motor vehicle safety standards.

IIHS

The crash tests done by the IIHS rates vehicles as good, acceptable, marginal, or poor based on their performance in high-speed front and side-crashes, plus evaluations of seat/head restraints for protection against neck injuries in rear impacts.

The “Top Safety Picks” are the best vehicle choices for safety within a size category.

For a vehicle to earn that label, it must first have good ratings in all three tests. It must also offer electronic stability control (ESC).

Euro NCAP

The Euro NCAP logo and star ratings have been in use since 1997 and have become internationally recognisable as a reliable indicator of independent consumer information about car safety. In Europe, all new car models must pass certain safety tests before they are sold.

The results can range from one to five stars, with five being the highest score. In February 2009, the rating system was changed to award an overall star rating for each car instead of a rating for each individual test.

This overall safety rating is composed of scores in four areas: adult protection, child protection, pedestrian protection and the safety potential offered by advanced driver assistance technologies such as electronic stability control. The overall score is calculated by weighing the four scores with respect to each other, while making sure that not one area is underachieving.

Over the next three years, stricter requirements will be introduced through a projected annual stepwise increase emphasising all-round safety performance and higher levels of achievement in each area.