[EdwardDiego]

1. Is a very hard question to answer, airborne lead pollution isn't fatal, but it does impact cognition. Perhaps ask yourself how many people lead lower quality lives because of it, and the flow-on effects from that lower cognition.

The people who did Freakonomics claimed that the drop in violent crime in the US in the 90s could be correlated to the phasing out of leaded fuel, but I'm not a statistician so can't speak to the accuracy of that correlation.

2. How would you even measure that? How would you define a better life thanks to a vehicle?

I feel like you're ice skating uphill a little given the deleterious effects of leaded fuels are well studied, but the question you're asking isn't.