Something to realize is that potential replacements to cars are not that much safer. Highway travel is responsible for 7.7 deaths per billion passenger-miles. Mass transit is responsible for 5.4 deaths per billion passenger-miles. Given the less-direct routings used by transit, it's not totally clear this is a meaningful difference.
All of this sucks - but it's the price we pay for being able to move a long distance quickly, something that seems to be a net benefit to society. (How many lives are saved by ambulances each year? How about by being able to easily visit a doctor?)
These are all statistics for the US in 2011. Sources are:
http://www.rita.dot.gov/bts/sites/rita.dot.gov.bts/files/pub... http://www.rita.dot.gov/bts/sites/rita.dot.gov.bts/files/pub... http://www.rita.dot.gov/bts/sites/rita.dot.gov.bts/files/pub...