U.S. ROADWAYS in 2016 yielded another bumper crop of carnage as vehicle fatalities soared 6 percent, following a 7 percent jump in 2015 — the biggest two-year spike since the 1960s. The cost of deaths, injuries and property damage resulting from crashes also leaped by 12 percent in just a year, to some $432 billion, an amount on par with the entire annual economic output of a mid-size European country, such as Norway.

It’s fair to assign some of the blame for the bloodshed to the quickening U.S. economy and relatively cheap gas prices, both of which prompted more drivers, especially collision-prone young drivers, to hit the roads for business and recreation. Yet the number of deaths as a percentage of miles driven also is increasing, meaning that the higher rates of vehicular death and destruction is very much impelled by the conduct of drivers and, critically, what government, particularly state government, is and isn’t doing.

The latest figures, from the nonprofit National Safety Council, which works closely with federal highway safety agencies, reflect what the organization’s chief rightly identified as a culture asleep at the wheel when it comes to roadway fatalities, which accounted for 40,200 deaths last year, roughly three times more than the toll exacted by gun violence. “Why are we okay with this?” said Deborah Hersman , NSC’s president and a former member of the National Transportation Safety Board. “Complacency is killing us.”

Specifically, complacency has led lawmakers to fritter away the gains made in roadway safety, mainly from technological improvements in cars and light trucks — rearview cameras; electronic stability control; automatic emergency braking and blind-spot monitoring — by easing up or turning a blind eye on traffic rules and enforcement, including for seat belts, speeding and drunken driving.

For instance, most states still do not allow police to ticket cars whose only offense is a failure by rear-seat occupants to wear seat belts — an inexcusable lapse given that more than half of all traffic fatalities involve unbelted occupants. In the past few years, more than a dozen states have raised speed limits on segments of their interstate highways. Many states are lax in requiring ignition interlocks, which prevent motorists with drunken-driving convictions from operating a car.

Add to all that the pervasive addiction of many drivers to their electronic devices, and the distraction posed by texting, Snapchat, map apps and in-vehicle, hands-free technology that may encourage motorists to use more functions on their phones while driving, interfering with their ability to concentrate. Safety advocates believe the temptations of technology are contributing to the soaring death rates.

Progress is possible through muscular laws and enforcement, including more speed cameras and tougher rules for seat belts, drunken driving and smartphone use. Without that and a greater focus to increase public awareness, the carnage will only increase.