It doesn't surprise me one bit.

"· People in busy roads more likely to be ill, says study
· Lack of traffic promotes sense of community

Mrs A lives in Dovercourt Road in north Bristol and considers five
people on her street as friends. But Mrs B, who is roughly the same
age and lives round the corner in a very similar house in Muller
Street, has only one friend.

The difference, says a study, has nothing to do with personality, but
is because of the weight of traffic. Fewer than 150 vehicles a day
pass down Dovercourt Road, compared with more than 21,130 a day on
Muller Street.

New research, based on interviews with households on three Bristol
streets, has found that people who live with high levels of motor
traffic are far more likely to be socially disconnected and even ill
than people who live in quiet, clean streets..."

"..."Growing car dependence is creating an epidemic of deteriorated
mental and physical health associated with air and noise pollution,
inactivity and road deaths and injuries."

More:

http://www.guardian.co.uk/environment/2008/sep/19/ethicalliving.automotive