Summer road trips mean more traffic deaths

The summer and early fall are the most dangerous times of year on the nation's roads, an updated IIHS analysis confirms. Fatalities also are higher on weekends and in the late afternoon and evenings, while Independence Day and New Year's Day have the highest average toll of any single date.

The trends reflect the fact that Americans drive the most miles during the warm summer months. Weekends and certain holidays with increased alcohol consumption also see spikes in deaths.

To find out when crashes are most likely to occur, IIHS researchers examined federal fatal crash data from 1998 to 2014. They chose that period because each day of the week occurred the same number of times, and every date except Feb. 29 fell on each day of the week at least twice. The study confirms many of the trends identified in an earlier IIHS analysis of traffic deaths during 1986-2002.

"Roadway deaths have declined since our original study, but the pattern of deaths is unchanged," says Charles Farmer, IIHS vice president for research and statistical services. "The riskiest times remain risky."

Annual traffic deaths fell during the new study period, with most of the drop occurring between 2007 and 2010. The number of fatalities averaged 106 per day during the 17-year period. 

As in the earlier analysis, weekends were deadlier than weekdays. There were an average of 139 deaths on Saturdays, compared with 89 on Tuesdays. The highest number of deaths occurred between 3 p.m. and 7 p.m. and the lowest between 3 a.m. and 6 a.m.

July and August were the deadliest months, with an average daily toll of 116. They were followed by June, October and September.

January and February had the lowest daily tolls and, not coincidentally, the lowest number of vehicle miles traveled.

Among January days, New Year's Day was an exception, with an average of 135 deaths. That's the second-highest after July 4, which had an average of 141 deaths.

The two holidays also were among the highest-fatality days in the previous study. Many communities conduct impaired-driving enforcement initiatives at those times of years, and the average number of fatalities has dropped on both days. However, Independence Day saw more progress, with fatalities falling 13 percent. In contrast, New Year's Day fatalities fell only 5 percent.

Pedestrian deaths, which comprised 12 percent of all traffic deaths during the study period, were generally highest in late November and early December, when days are getting shorter. Jan. 1 was the worst single day for pedestrian deaths.

Motorcyclist deaths accounted for 10 percent of fatalities. July 4 had the highest number of motorcyclist fatalities, and the other dates in the top 10 also were in warm-weather months.

Deaths by month

Average number of deaths per day, 1998-2014

Deaths by day of the week

Average number of deaths per day, 1998-2014