Seat belts work; they save lives. So if you never start the car without buckling up, bravo! Keep doing it. If you sometimes (or often) drive or ride without wearing a seat belt, think about the following statistics and reconsider your behavior.

Motor vehicle crashes are the leading cause of death in the United States for people between the ages of four and 34. Overall, car crashes are the eighth leading cause of death — and the number-one cause of head and spinal-cord injuries. Despite the advances we've made over the years — seat belts, air bags, better designed cars, higher drinking-age laws, and helmets for motorcyclists — the toll taken by motor vehicle accidents is enormous. And we can do better.

More than 25 countries have some type of mandatory seat belt laws. The laws work, too — rates of usage have gone from about 20 to 25 percent before the laws were enacted to 60 to 90 percent after. And although seat belt usage is at an all-time high of 82 percent nationwide (due in no small part to those laws), 43,200 Americans died on the nation's highways in 2005 — up from 42,636 in 2004. According to the National Highway Traffic Safety Administration (NHTSA), the majority (55 percent) of those killed in passenger vehicles were not wearing their seat belts.

When used properly, seat belts decrease the number of serious injuries by 50 percent and reduce fatalities by 60 to 70 percent. And if you think you don't have to wear one when you're driving just to the local store, think again. Seventy-five percent of crash injuries and deaths occur within 25 miles of home, and more than half of all the injury-producing accidents occur at speeds less than 40 miles per hour. Here are some other sobering 2005 statistics from the NHTSA:

• Use of safety belts makes a significant difference in whether you end up in the hospital or not. One person in six who was wearing a seat belt at the time of a crash went to the hospital compared with one in three who wasn't wearing a seat belt.

• Getting thrown from a vehicle is usually an injurious or fatal event. In fatal crashes in 2004, 74 percent of people who were thrown from a vehicle were killed; that's three out of every four people! Safety belts prevent people from being ejected from vehicles: Only 1 percent of people wearing belts were thrown out of vehicles versus 29 percent of those not wearing belts.

• Lap/shoulder safety belts work. When used correctly, they reduce the risk of fatal injury to people sitting in the front seat by 45 percent and the risk of moderate-to-critical injury by 50 percent. For light-truck occupants, the track record is even better: reducing the risk of fatal injury by 60 percent and moderate-to-critical injury by 65 percent.