<p>AMERICANS drive a staggering number of miles -- close to three trillion every year, according to the government. (That is half a light-year, or 120 million trips around the world.) And although traffic accidents remain a major public safety problem, the biggest killer of people ages 5 to 34, vehicle travel is far safer than it was a few decades ago. </p><p itemprop=&quot;articleBody&quot;> Several factors appear to account for the sharp decline in fatalities. Technology (like antilock brakes and air bags) and road behavior (like wearing seat belts and driving sober) have both improved greatly since 1950. </p><p itemprop=&quot;articleBody&quot;>&nbsp;</p><p itemprop=&quot;articleBody&quot;>기사원문보기 : <a href=&quot;http://query.nytimes.com/gst/fullpage.html?res=9C01E4DB1E31F93BA2575AC0A9649D8B63&amp;partner=rssnyt&amp;emc=rss&quot;>http://query.nytimes.com/gst/fullpage.html?res=9C01E4DB1E31F93BA2575AC0A9649D8B63&amp;partner=rssnyt&amp;emc=rss</a></p>