WASHINGTON — The government said traffic deaths surged last year as drivers racked up more miles behind the wheel than ever before.

The National Highway Traffic Safety Administration said preliminary estimates show fatalities rose 7.7 percent to about 35,200 in 2015. That’s makes last year the deadliest driving year since 2008.

Safety experts cited several reasons for the rebound in fatalities. The most significant is that an improved economy and low gas prices led to a record 3.1 trillion miles driven.

Historical data show that after peaking in the 1970s, crash deaths have fluctuated considerably while generally trending downward. Large dips have corresponded to economic shocks, and gas price hikes.

Manufacturing steps up in June

WASHINGTON — American manufacturing expanded for the fourth straight month in June, hitting the strongest reading in 16 months as the outlook for new orders improved.

The Institute for Supply Management said its manufacturing index rose to 53.2 last month from 51.3 in May. Anything above 50 signals growth.

The report suggests U.S. factories are showing some signs of stability after being pummeled at the beginning of last year by a rising dollar, shuttered oil production and weak global economic growth.