Kids living near major roads at higher risk of developmental delays. Young children who live close to a major roadway are twice as likely to score lower on tests of communications skills, compared to those who live farther away from a major roadway, according to a new analysis. Source 4t.
I'm assuming it has to do with a lot of sensory issues to do too much 'noise pollution' from the environment. Not to mention other pollution such as air since vehicles emit too much of these harmful gases which affects physical development too.