Crown Wellness Center Blog

Why is it important to know the rating of your seat/head restraint?

When the average consumer buys a car, they generally never think to check on effectiveness of the head restraint to prevent “whiplash” injury.

The Insurance Institute for Highway Safety (IIHS), an organization funded by insurance industry, has performed crash testing research that shows Whiplash Injury occurs in automobile rear impact crashes with speeds as low as 20mph. So it is important to know how your vehicles headrest performed in these crash test studies. If a head restraint isn’t behind and close to the back of the head, then it cannot prevent whiplash injury. Since 1995, the IIHS have been testing and publishing the results of the model-by-model ratings of the head restraints.

The crash test is performed in a 2 Phase study, which is outlined below:

Phase I: The test consists of measuring the height and distance of the restraint from the back of the head of an average sized man. The restraint (head rest) should be at least as high as the head’s center of gravity (3.5 inches) below the top of the head. The distance behind the head, should be as small as possible. If more than 4 inches exists than increased symptoms of neck injury (whiplash) have been associated. Each restraint (head rest) is classified according to its height and backset into one of four geometric zones: good, acceptable, marginal or poor.

Phase II: consist of dynamic sled test. This test consists of recreating a rear end collision simulated at a 20mph crash. It is important to note that vehicle’s whose head restraint rated marginal or poor in Phase I are not tested in dynamic sled test because Neck Injury “Whiplash” is inevitable in a rear end collision.

This table is a small sampling of tested vehicles: