And there are other conflicting safety trends: Drunk driving accidents are down, but distracted driving crashes are on the rise. Overall traffic fatalities dropped 1.9 percent, to 32,367. In 1949, 32,246 people died in car crashes. Fatalities peaked in the early 1970s, when more than 50,000 people died several years in a row.
The 2011 decline came as the number of miles driven by motorists dropped by 1.2 percent. More people died in distraction-related crashes, up 1.9 percent compared with 2010, but that may not mean more people are texting while driving. NHTSA said the increase could be, in part, because more emergency responders are aware of the issue and are doing a better job reporting it.
Deaths of bicyclists and occupants of large trucks rose sharply last year even as total traffic fatalities dropped to their lowest level since 1949, federal safety officials said Monday.
Bicyclist deaths jumped 8.7 percent and deaths of occupants of large trucks increased 20 percent, the National Highway Traffic Safety Administration said in an analysis of 2011 traffic deaths.
Overall traffic fatalities dropped 1.9 percent, to 32,367. The decline came as the number of miles driven by motorists dropped by 1.2 percent.
Last year also saw the lowest fatality rate ever recorded, with 1.10 deaths per 100 million vehicle miles traveled in 2011, down from 1.11 deaths per 100 million vehicle miles traveled in 2010.
The increase in bicycle deaths probably reflects more people riding bicycles to work and for pleasure, said Jonathan Adkins, deputy executive director of the Governors Highway Safety Association, which represents state highway safety agencies.
Washington, D.C., for example, reports a 175 percent increase in bicyclists during morning and evening rush hours since 2004. The city also tripled its bike lane network during the same period.
"Our culture is beginning to move away from driving and toward healthier and greener modes of transportations," Adkins said. "We need to be able to accommodate all these forms of transportation safely."
The increase in deaths of large-truck occupants is more puzzling, but may be due to more trucks returning to the road as the economy improves, he said.
"There are more questions than answers about what is occurring here," Adkins said. NHTSA said the agency is working with the Federal Motor Carrier Administration to gather more information to better understand the reason for the increase.
Motorcycle deaths also rose 2.1 percent, marking the 13th time in the last 14 years that motorcycle rider deaths have risen.
The Associated Press contributed to this report.