The number of people who were killed in large-truck crashes increased for the fourth straight year, bucking a trend of overall improvement in U.S. highway safety. Fatalities rose to 3,964 people in 2013, which includes truckers, pedestrians and the occupants of vehicles that collided with the big rigs, the U.S. Transportation Department stated last month in its annual traffic-injury report That’s up 0.5 percent from 2012, even though highway deaths involving all types of vehicles fell 3.1 percent to 32,719.

Regulators said new federal standards requiring stability-control technology to prevent rollovers, and future rules that may require stronger underride guards on the backs of semi-trailer can help reverse the trend. David Friedman, the Deputy Administrator of the National Highway Traffic Safety Administration, told the media:

We do know tired truckers are a risk on our roads. Any effort to reduce the number of people who are tired or drowsy on the road can have an impact.

Interestingly, the report was issued just a week after Congress suspended part of it set of regulations intended to ensure truckers get adequate rest. Lawmakers targeted a portion of the rule closing a loophole that kept some drivers from working 82 hours over eight days. That provision won’t be enforced for at least a year as regulators conduct research to see if it had an unintended effect of forcing more trucks onto the road during rush hours. Federal regulators will monitor whether the new policy affects the fatality count. Transportation Secretary Anthony Foxx stated:

The hours-of service rule is a critically important rule. Critical pieces of it have now been changed.

While the overall state of highway safety may be improving, and hopefully it is, there are far too many deaths and serious injuries occurring each month. Besides the decline in all kinds of traffic deaths in 2013, the year tied an all-time record for the lowest fatality rate-1.1 people were killed for every 100 million vehicle-miles traveled.