Japan's overall air pollution has been getting better in the last 30 years, but smog from cars and trucks has been going up. People from Nagoya actually sued the government, saying that freeway construction harmed their health and they deserved compensation for asthma and other illnesses. I think they lost, but still it's a serious problem. That's one of the reasons for the huge tolls, expensive inspections, and subsidies for hybrids and fuel cells. In some places, idling like that is illegal.