Over the long-term, primary safety belt use laws benefit everyone. When combined with highly visible enforcement, public education, and adjudication States and community experience lower fatality rates and economic savings. The following research highlights various aspects of these benefits.
NHTSA researchers compared the percentage of unrestrained passenger vehicle occupant fatalities and fatality rates between those States that had and those that did not have primary safety belt use laws from 2000 to 2004. Results not only showed a smaller percentage of unrestrained passenger vehicle occupant fatalities in primary enforcement States (51 percent compared to 65 percent), they also showed significantly lower fatality rates. This was true whether the fatality rate was based on vehicle miles traveled (VMT) or population. In primary enforcement States the passenger vehicle occupant fatality rates were 1.03 per 100 million vehicle miles traveled (VMT) and 10.69 per 100,000 population. This compares to 1.21 and 13.13 (respectively) for all other States.20
In December 2004, the Insurance Institute for Highway Safety published a study21 designed to estimate the effect that a change from a secondary to a primary law would have on driver fatality rates. The results of the study showed that, “After accounting for possible economic effects and other general time trends, the change from secondary to primary enforcement was found to reduce annual passenger vehicle driver death rates by an estimated 7 percent…”22
The study examined driver fatality data from 1989-2003 in 10 jurisdictions where secondary laws were amended to primary laws. The jurisdictions were California, the District of Columbia, Georgia, Indiana, Louisiana, Maryland, Michigan, New Jersey, Oklahoma, and Washington. Researchers compared these data with data in States where the laws remained secondary. The annual rate of passenger vehicle driver deaths per mile of travel declined in both groups of States, but it declined more in the States that changed to primary enforcement.
As quoted in the Institute’s newsletter, “…during the study period “many States participated in special Click It or Ticket safety belt enforcement campaigns. The enhanced enforcement began earlier in the primary States so it’s important to note that changes in belt use laws along with the increased enforcement led to the decrease in fatalities.” Based on the reduction in driver death rates, it’s estimated that 2,990 lives have been saved in the study States because of the tougher safety belt laws. “If the 27 States that still have secondary laws were to switch to primary enforcement, about 700 lives would be saved each year. And if legislators in these States had enacted primary laws to begin with, more than 5,000 lives could have been saved since 1996.”23
The following information from the study (Table 4) shows the number of lives that could have been saved for each State that had a secondary safety belt use law.
Table 4 Effects Of Strengthening Belt Laws:
Lives that could have been saved since 1996 in secondary States if belt laws had been primary
Another study, “Lives Lost by States' Failure to Implement Primary Safety Belt Laws,”24 calculated that failure to implement primary laws in all States resulted in more than 12,000 lives lost during the years 1995 - 2002. To reach this conclusion, researchers conducted analyses that provided three estimates of the effectiveness of primary laws; all of which suggested that belt use was likely to increase approximately
Increasing the national safety belt use rate has tremendous potential for reducing the economic costs associated with crashes, along with saving lives and preventing injuries. For example, increasing the national safety belt use rate from 82 percent (the rate measured in 2005) to 90 percent would:
These economic cost savings result from reduced productivity losses, property damage, medical costs, rehabilitation costs, legal and court costs, emergency services costs, insurance administration costs, funeral costs, traffic delay, and costs to employers.25