Preliminary estimates from the National Safety Council (NSC) indicate road deaths in the first six months of 2017 are 1% lower than they were one year ago, but still 8% higher than the same period in 2015.

However, the country is fresh off the steepest estimated two-year increase in motor vehicle deaths since 1964, and it is too early to conclude whether the upward trend is over, the NSC says.

An estimated 18,680 people have been killed on U.S. roads since January and 2.1 million were seriously injured. According to the NSC, the final six months of the calendar year – July to December – tend to be deadlier than the first six.

“The price of our cultural complacency is more than a hundred fatalities each day,” said NSC President and CEO Deborah A.P. Hersman. “Although the numbers may be leveling off, the Road to Zero deaths will require accelerating improvements in technology, engaging drivers and investing in our infrastructure.”

The NSC estimated as many as 40,000 people were killed on the roads in 2016 – a 6% rise over 2015 and the largest two-year percentage increase in deaths in 53 years. Those estimates – as well as the 2017 preliminary estimates – are subject to slight increases and decreases as the data mature.