Deaths behind the wheel of an automobile fell last year to the lowest level since the Truman administration, but there was an increase in fatalities among bicyclists, pedestrians, motorcycle riders and big-rig truck drivers, according to federal figures released Monday.

Overall, traffic deaths dropped to 32,367, almost 2 percent lower than the 2010 total, and a 26 percent decline since a peak in 2005.

The downward national trend began before the recession took some drivers off the roads, and it accelerated last year. It has been attributed to several factors, including increased use of air bags, seat belts and other vehicle safety features, improved roadway designs, and increasing awareness of the perils of driving drunk...

...The number of bicyclists killed increased by 8.7 percent, and pedestrian deaths were up 3 percent...[There was] an increase of more than 2 percent in motorcycle deaths...

...The largest increase was a 20 percent jump in the number of drivers and passengers of large trucks killed in accidents.