From the CDC<p>&quot;In 2013, 10,076 people were killed in alcohol-impaired driving crashes, accounting for nearly one-third (31%) of all traffic-related deaths in the United States.&quot;<p>&quot;Drugs other than alcohol (e.g., marijuana and cocaine) are involved in about 18% of motor vehicle driver deaths. These other drugs are often used in combination with alcohol.&quot;<p><a href="http:&#x2F;&#x2F;www.cdc.gov&#x2F;motorvehiclesafety&#x2F;impaired_driving&#x2F;impaired-drv_factsheet.html" rel="nofollow">http:&#x2F;&#x2F;www.cdc.gov&#x2F;motorvehiclesafety&#x2F;impaired_driving&#x2F;impai...</a><p>So with 31+% of deaths related to alcohol, I&#x27;d put that as the greatest threat.  The problem with all accident stats is that one accident creates many stats.  Say a drunk hits a tree.  One person says it was &quot;speed related&quot;, another blames a distraction, another the lack of devices to prevent the car leaving the road, another the driver not using a seat belt or airbag ... and we all know it begins with the drunk.<p>I eagerly wait for Google to allow drunks to use these cars.  That &quot;the car gets you home&quot; scenario is what supporters champion when they talk of reducing accidents.  But I doubt Google&#x27;s lawyers will ever remove &quot;do not drink and drive&quot; from the car&#x27;s manual.