Air pollution is blamed for increases in road accidents

[guohua]

OK, now Please read this article closely because I'm going to asked a guestion about the PhD Student who's making this Claim!

A PhD student at the London School of Economics found that the number of accidents on British roads fluctuated in line with levels of nitrogen dioxide.

Heavy pollution makes people drive more dangerously, according to the first study to link dirty air with road accidents.
Scientists have already established that being exposed to airborne pollutants such as ozone and microparticles of soot even for a few hours can harm children’s test scores at school and make workers in factories and call centres less productive.
Now Lutz Sager, a PhD student at the London School of Economics (LSE), has shown that breathing in air pollution has a similar judgment-impairing effect on drivers.

Source

Now do you know what guestion I'm Going To Ask?
What does a PhD Student of Economics know about know about Nitrogen Dioxide and car accidents?

Beside, the Smog in L A Cal. in the 70's was 10 times worst than anything you'd see today, except for a Really Bad Day in China.
But still, Mr.G. said that you couldn't see across the street in California in the 60's and 70's. Did they have a raise in car accidents?