Each year, the National Highway Traffic Safety Administration makes a detailed analysis of auto accident statistics in the U.S. Compiling and studying the data takes a long time, and the full reports are not ready until about 18 months after the end of the calendar year. But a preliminary report on auto accident fatalities in 2012 has just been released, and the early indications are a bit troubling.

The NHTSA estimates that 34,080 people died in auto accidents on U.S. roads in 2012. If that estimate holds true, it represents an increase of about 5.3 percent over 2011 fatalities, which numbered 32,367. What many do not realize is that the U.S. has enjoyed a decrease in traffic fatalities each year since 2005, when the figure was 43,510. Last year will therefore likely mark a break in a strong and very positive trend in safety.

Vehicle miles traveled (VMT) increased by 0.3 percent to 9.1 billion and therefore only account for a small portion of the increase. The estimated fatality rate per VMT for 2012 is 1.16 per 100 million VMT, up from 1.10 in 2011. In plain English, this means that U.S. drivers are driving slightly more, but dying at a higher rate for every mile spent behind the wheel. Like the total number of fatalities, the fatality rate declined each year from 2005 to 2011.

The number of miles driven varies throughout the year. People drive more during the summer and holidays. The hazards of the road vary as well – more accidents occur during rainy and snowy months. Therefore, it is useful to compare accidents from a given quarter of one year with the same quarter from the previous year. The NHTSA report illustrates the strength of the earlier downtrend in traffic fatalities by showing that from 2006 to 2010, there were 17 consecutive quarters that showed a year-over-year decline. That is the single longest unbroken downtrend since the agency began compiling auto accident statistics in 1976.

Although any increase in traffic deaths is disheartening, this report should be taken in context. Deadly accidents have fallen steeply over the past several years. The U.S. is making significant strides in road safety. Hopefully, 2012 statistics will turn out to be an anomaly and fatal auto accidents will continue their longer-term downtrend in 2013 and beyond.