Excessive speed is among the leading reasons more people suffered serious injuries from car accidents last year.

Car accident frequency takes wrong turn in 2015

Traffic safety numbers are in from 2015 and the news isn't good, as despite painstaking efforts from public interest groups and government officials about driving defensively, serious motor vehicle accidents rose appreciably last year.

At 35,200, nearly 8% more Americans were killed on the nation's highways in 2015, according to preliminary figures released in early July by the National Highway Traffic Safety Administration. In 2014, 32,675 individuals lost their lives in automotive collisions.

Mark Rosekind, NHTSA Administrator, said that there are likely several reasons for the discouraging trend, including the fact that with more people on the roads – due to the combination of lower gas prices and an improving economy – accident frequency tends to follow suit.

"But that only explains part of the increase," Rosekind explained. "[The overwhelming majority] of crashes (94%) can be tied back to a human choice or error, so we know we need to focus our efforts on improving human behavior while promoting vehicle technology that not only protects people in crashes, but helps prevent crashes in the first place."

Fairly recent technological advancements have helped to make this possible in some respects. Earlier this year, the Insurance Institute for Highway Safety reported from its calculations that automatic braking cut rear-end collisions by as much as 40%. In fact, had every registered motor vehicle been outfitted with this safety feature, rear-enders would have been reduced by 700,000.

At the same time, however, automatic braking features aren't foolproof, meaning that behaviors can override their effectiveness and some people may opt to not activate them where this option is available.

CDC: US No. 1 in serious car collisions

The high amount of deadly car accidents takes on greater magnitude when analyzing the numbers from an international perspective. For example, the U.S. Centers for Disease Control and Prevention recently released its annual Vital Signs analysis, detailing motor vehicle injuries in 19 different countries, including Belgium, England, Sweden, Japan, Spain, Slovenia, Germany, and France, among others. At 10.3 fatal accidents per 100,000, the U.S. had the highest deadly accident rate of the 19 countries analyzed, even though the rate fell 31% compared to 2000. In the other countries, the decline over the same 13-year stretch was more precipitous at 56%.

"The National Safety Council is frustrated to see the unacceptably high death toll that shows the United States has the highest rate of motor vehicle deaths among 19 high-income comparison countries, according to the latest Vital Signs report from the Centers for Disease Control and Prevention," said the National Safety Council in a prepared statement after the CDC report was released. "These data provide yet another sad commentary on the state of safety on our nation's roadways."

NSC went on to say that even though vehicles today have more advanced safety components than ever, the fact that 100 people die in car accident daily is unacceptable and cannot be tolerated.

"The question is not 'Why are our roadways so deadly?' The questions today should be, 'Why do we accept this?' and 'What more can we do?'" the press release from the NSC further stated.

Seat belts can cut roadway fatalities by 3,000

The solution may be literally under motorists noses: seat belts. Even though more people are, in fact, buckling up – 89% of Americans regularly strapped themselves in 2015, up from 85% in 2010, according to NHTSA data – it's still far away from 100% compliance.

Erin Sauber-Schatz, Ph.D., head of transportation security for the CDC's National Center for Injury Prevention Control, said that if a higher percentage of people used their seat belts, the troublesome trend would be less severe.

"About 3,000 lives could be saved each year by increasing seat belt use to 100%," Sauber-Schatz explained.

Since NHTSA started keeping track of seat belt compliance, the usage rate has never reached or topped 90%. Safety experts are hopeful that Americans will make history in 2016 and reclaim the strides made in the early 2000s.