Motor vehicle accidents killed 42,642 people in 2006, according to the National Highway Traffic Safety Administration (NHTSA). That's the lowest level in five years and a drop of 2 percent from 2005. Injuries from crashes also declined for the seventh year in a row. Among those killed, 55 percent were not wearing seat belts.

The number of occupents killed or injured decreased for all vehicles except SUVs, where occupant deaths rose by 1.6 percent. (SUVs had the largest increase in registrations, so there are more of them on the road.) And deaths by rollovers declined by 1.6 percent except for pickups, where they rose 1.6 percent.

There was no significant change from the previous year in the number of those killed in alcohol-related crashes in 2006 — they account for 41 percent of traffic deaths. There was also little change among crash-related deaths for young drivers age 16 to 20: The number of those killed increased 0.7 percent to 3,406 and the number of young drivers involved in fatal crashes declined 0.3 percent to 6,984.

Among children, traffic deaths declined for all ages, and 8- to 15-year-olds experienced the biggest decline, 11 percent, to 1,270.

NHTSA's 2006 numbers show that there is little safety difference in driving at daytime vs. nighttime: 20,510 deaths occurred during the day and 21,793 happened at night.

Deaths and injuries of motorcycle riders are a serious concern of NHTSA. Those deaths increased for the ninth straight year and now account for 11 percent of fatalities. Department of Transporation Secretary Mary Peters has announced a 2007 Motorcyle Action Plan, which hopes to reduce those numbers with more rider education, stricter standards for helmet certification labeling, more law enforcement training on how to spot unsafe motoycyclists and road designs that are better for motorcycles. There will also be a public awareness campaign on safe riding techniques.