Emergency responders work at the scene of a two-vehicle crash on Nov. 9 in Erie County, Pa., that killed both drivers. (Andy Colwell/AP)

The number of drivers and passengers killed in traffic crashes declined to a record low last year, but pedestrians died at a higher rate, and the overall trend so far this year is alarming, the National Highway Traffic Safety Administration said Tuesday.

The 32,675 traffic deaths last year were the lowest ever, but NHTSA Administrator Mark R. Rosekind said that estimates for the first six months of this year show that fatalities are up more than 8 percent.

“I always cite the exact number, because every one of those is a life,” Rosekind said in a conference call with reporters. “Zero is the only acceptable number.”

The federal agency gathers its data from police reports collected by states. Rosekind said that until complete reports are filed, his agency lacks the detail necessary to determine the cause of this year’s increase.

He underscored the research that indicates that human error is a factor in an estimated 94 percent of crashes.

“The last element before a crash happens has to do with the human,” Rosekind said. “It has to do with either an error they made or a choice they made. That choice could be speeding, not wearing their seat belt, not wearing a helmet, not securing a child in a car seat. Drunk, drugged, drowsy — those are things that people choose to do and then get behind the wheel.”

The number of people killed in car crashes has been on a fairly steady downward track for the past six years, primarily because of safety features that have been built into cars and trucks.

From increased seat-belt use to air bags to anti-lock braking to stability controls that keep cars from flipping to a new generation of electronic warnings and cameras, cars today are far safer than they were a generation ago.

“That’s why there’s so much excitement about potential for new safety technologies that could help offset or mitigate those kinds of human errors or decisions,” Rosekind said.

The data released Tuesday also reveals the following:

●9,967 people died in drunken-driving crashes, about a third of all fatalities.

●Almost half of those who died in passenger-vehicle crashes were not wearing seat belts.

●The death rate for motorcyclists was much higher in states without strong helmet laws.

●3,179 died in incidents of distracted driving, about 10 percent of all crash fatalities.

●At least 846 people died in drowsy-driving incidents, about 2.6 percent of all crash fatalities.

●Deaths of bicyclists declined by 2.3 percent from 2013; 726 cyclists were killed.

●Pedestrian deaths rose by 3.1 percent from the previous year; 4,884 pedestrians were killed in motor-vehicle collisions.

This year, Rosekind said, “We have seen increases in the vulnerable populations: pedestrians and bicyclists.”

The Governors Highway Safety Association reported in September that the number of drivers killed in crashes who tested positive for drugs had increased to 39.9 percent in 2013 from 29 percent in 2005.

The GHSA, an organization of state highway-safety officials, said that the use of illegal drugs and abuse of prescription drugs played an increased role in auto crashes in the past five years. The group drew its conclusions from analysis of NHTSA roadside surveys.

A quadrupling in the use of prescription drugs since 1999 and legalization of marijuana use in some states were among the reasons drug use has become an increasing threat to roadway safety, the GHSA said.

The report says drugs were found in the bodies of nearly 40 percent of fatally injured drivers who were tested for them. That rivals the number of drivers who died with alcohol in their system.

An analysis by the AAA Foundation for Traffic Safety a year ago determined that drowsy drivers were at fault in a much higher percentage of crashes than NHTSA once thought.

The foundation said that 21 percent of fatal crashes were caused when a driver dozed off behind the wheel.

The foundation analyzed 14,268 crashes between 2009 and 2013 in which at least one vehicle was towed from the scene. Researchers said that a third of accidents involving a fatigued driver resulted in injuries and that more than 6,000 tired-driver crashes each year resulted in at least one death.

The AAA foundation came up with another disturbing statistic in March after analyzing nearly 1,700 videos of crashes involving teenage drivers. The foundation found that distracted driving was a factor in 58 percent of those accidents, about four times higher than previous estimates based on police reports.

The analysis indicates that about a half-dozen types of distraction were the cause, led by interacting with other passengers, which was blamed in 15 percent of crashes. Cellphone use resulted in 12 percent of accidents, followed by looking at something inside the car, looking at something outside other than the road ahead, singing or moving to music, grooming and reaching for something.

Overall, however, the number of people who died in crashes involving teen drivers dropped by 56 percent, and the number injured declined by 51 percent, according to federal data for 1994 to 2013.

Teenage drivers have the highest crash rate of any age group. And 40 percent of the people killed — as well as half of those injured — in those crashes are not in the teen driver’s vehicle.

NHTSA said Tuesday that it will hold a series of meetings across the country next year, ending with a gathering in Washington, to generate new approaches to dealing with the human issues that contribute to road deaths. Rosekind said the meetings will address drunken, drugged, distracted and drowsy driving; speeding; failure to use seat belts and child seats; and new initiatives.

“While great public attention is focused on safety defects and recalls, and rightfully so, it is time as a nation to reinvigorate the fight against drunk and drugged driving, distraction and other risks that kill thousands every year,” Rosekind said.