Behavioral choices — such as speeding, driving while drunk, texting or not buckling up — are fueling a highway death rate that increased more in 2015 than in half a century. After decades of decline, fatalities jumped by more than 7 percent that year, and early figures indicate that 2016 may be an even deadlier year. Nearly half of the 2015 fatalities involved an unbelted passenger or driver and about one-third were alcohol-related. Experts say stronger laws and beefed-up public awareness programs would help. And they say technological developments, including automatic braking and collision avoidance, also will save lives. Distracted driving raises new concerns: As more cars include hands-free capabilities for smartphones as standard equipment, safety experts warn that use of such devices is as dangerous as talking on hand-held versions. Self-driving cars are on the road in California, Pennsylvania and elsewhere, potentially adding another dimension to the possible safety solutions but raising new questions around the life-and-death choices the software programs in those vehicles must make.