Proximity to freeways increases autism risk, study finds - LA Times Children born to mothers who live close to freeways have twice the risk of autism, researchers reported Thursday. The study, its authors say, adds to evidence suggesting that certain environmental exposures could play a role in causing the disorder in some children. "This study isn't saying exposure to air pollution or exposure to traffic causes autism," said Heather Volk, lead author of the paper and a researcher at the Saban Research Institute of Children's Hospital Los Angeles. "But it could be one of the factors that are contributing to its increase." Children living about 1,000 feet from a freeway at birth about 10% of the sample had a two-fold increase in autism risk. The link held up even after researchers controlled for other factors that may influence development, such as ethnicity, parental education, maternal age and exposure to tobacco smoke. The study did not find a link between autism development and proximity to a major road, as opposed to a freeway. That may be due to the type and quantity of chemicals dispersed on freeways compared with major roads, Volk said. In Los Angeles, some freeways carry more than 300,000 vehicles daily.