In this April 28, 2016 file photo, a wrecker crew prepares to flip over a Ford Bronco that was involved in a crash in Brownsville, Texas. (Jason Hoekema/The Brownsville Herald via AP, File) (Jason Hoekema/AP)

A more rosy economy has cast gloom over U.S. roadways, with thousands more people dying in car crashes in the past 18 months.

Data released Monday shows that 2,348 more people died in crashes last year than in 2014, according to the National Highway Traffic Safety Administration’s annual recap of traffic fatalities. That 7.2 percent increase translates to a total of 35,092 people killed on U.S. roads.

In addition, the numbers of pedestrian and bicyclist deaths were greater than at any other time in the past two decades, and motorcycle fatalities reached the highest number since 2012.

“Despite decades of safety improvements, far too many people are killed on our nation’s roads every year,” Transportation Secretary Anthony Foxx said.

The bad news was compounded last week when the independent National Safety Council said preliminary statistics showed that the number of traffic deaths was 9 percent higher in the first six months of this year than during the corresponding period in 2015.

“The improving economy is one likely cause of the increase in traffic deaths,” said Russ Rader of the Insurance Institute for Highway Safety. “Historically, traffic deaths decline during recessions as the unemployment rate rises, and then increase again as the economy picks up and unemployment declines.”

Four avoidable factors were blamed for the majority of the fatal crashes. NHTSA said alcohol-related fatalities increased by 3.2 percent, from 9,943 in 2014 to 10,265 in 2015; the number of fatal crashes in which distracted driving played a part increased by 8.8 percent, from 3,197 to 3,477; crashes linked to speeding increased by 3 percent, from 9,283 to 9,557; and the number of victims not wearing a seatbelt increased by 4.9 percent, from 9,410 to 9,874.

“The data tell us that people die when they drive drunk, distracted or drowsy, or if they are speeding or unbuckled,” said NHTSA Administrator Mark Rosekind. “While there have been enormous improvements in many of these areas, we need to find new solutions to end traffic fatalities.”

Rader added: “If we were to double down on tackling drinking and driving, reducing speeding, and getting more people buckled up, it would make a big difference. The increase we’re seeing now wouldn’t be as large.”

The deaths of 5,376 pedestrians marked a 9.5 percent increase over 2014. The 818 cyclists killed represented a 12.2 percent increase. Motorcycle fatalities were up by 8.3 percent to 4,976, the highest number since 2012.

Traffic deaths declined by almost 10 percent as unemployment peaked in 2007-2008. By 2014, the number of fatalities had dropped to 32,744, the lowest ever.

“The miles-traveled that come back after a recession are riskier miles,” Rader said. “Optional, more hazardous travel returns, like going out at night and on the weekends, or taking long trips on unfamiliar roads.”

Since 1990, more than 1 million people have died in crashes on U.S. roads, and the World Health Organization says there are about 1.25 million global traffic deaths each year.

Jonathan Adkins, executive director of the Governors Highway Safety Association, an organization of state highway-safety officials, called the 2015 federal data “an urgent wake-up call that highway safety needs to be a national priority.”

The National Safety Council last week estimated that 19,100 people died in crashes during the first six months of this year, an 18 percent increase since 2014. An additional 2.2 million people suffered serious injuries.

“Our complacency is killing us,” said Deborah A.P. Hersman, president of the safety council and a former chairman of the National Transportation Safety Board. “One hundred deaths every day should outrage us.”

The council said traffic fatalities have skyrocketed in seven states since 2014. They increased by 43 percent in Florida, 34 percent in Georgia, 33 percent in Indiana, 31 percent in California, 26 percent in North Carolina, 24 percent in Illinois and 24 percent in Kentucky.

The organization estimates that 438 people will die this Labor Day weekend, the highest number the group has ever projected for the weekend that marks the traditional end of summer.

“Americans should demand change to prioritize safety actions and protect ourselves from one of the leading causes of preventable death,” Hersman said.