Car accidents are one of the biggest health risks we face, and last week that risk jumped higher. July Fourth is typically one of the worst days of the year for traffic fatalities.

The best things you can do to protect yourself in a car are to wear a seat belt, obey traffic laws and don't drink and drive. What you drive can also make a difference. Now there are a number of Web sites that show just how well your car held up in a crash.

Last fall, a study by the Insurance Institute for Highway Safety (IIHS) showed that safety improvements in the design of passenger vehicles — not safer drivers — are the reason motor vehicle death rates have been improving for the past decade. The study found an "increasingly dangerous traffic environment" and that drivers are actually getting more careless about seat belts, speeding and driving while intoxicated. In fact, the study showed that if vehicle designs hadn't improved since 1985, traffic death rates would be on the rise.

Although most cars now come with airbags and anti-lock brakes, crash test studies show there's a big difference in safety among cars today. One of the best places to check out your car is www.iihs.org. Click on "Vehicle Ratings." The IIHS is supported by auto insurers and is viewed as one of the most credible sources for research on car safety. The group publicizes the best performers in crash tests, but many consumers don't know the safety data is free online.

The IIHS vehicle ratings page lists its top picks for 2007, the first year the institute has rated cars for electronic stability control, which helps drivers maintain control in an emergency. Research has shown that ESC features significantly reduce the risk of dying in a car accident.

I've been checking out minivans and was surprised to see that the Hyundai Entourage and Kia Sedona were the only two top IIHS picks in the category. The site ranks cars as good, acceptable, marginal or poor in various tests. I searched the Honda Odyssey, which posted "good" scores for front and side crash tests, but make sure you hit the "compare" button at the bottom, which lets you compare a car with others in its class. The Odyssey only scored "marginal" on rear crash tests. The Toyota Sienna and Nissan Quest, received poor rankings in rear tests.

Another feature allows you to click on Front, Side or Rear to look at even more detailed crash test analysis. The Nissan Quest and Ford Freestar both had a "good" overall score on front crashes but scored only "acceptable" for head and neck injuries. The Odyssey had a good overall score for side impact, but rear passenger safety in a side impact was only "acceptable" for torso injuries.