$41-52 billion / 254 million vehicles = $161 / yr * 13 years = $2,100-$2,500. From the US.
$20-250B in military expenditures to protect oil supplies / 254 million vehicles = ($80-900
32% of Fossil fuel burning (aka not coal) is transportation. It's estimated by the National Academy of Sciences that $120B
So all told we're conservatively looking at:
$2,050 + $6,350 + $2,300 = $10,700
That's before you look at environmental impacts and climate change.