From a site advising students travelling to Japan:
Drinking and driving in Japan is not tolerated and the drink-drive level is zero percent. Even a glass of wine or a beer can result in heavy fines or the loss of your license if you are stopped and checked. If you cause an accident you may lose your license permanently.
It obviously can be done and a national community can find it acceptable. But I think the situation is very long standing in Japan.
Nevertheless, it doesn't stop people from drink-driving as this yahoo article indicates:
http://ca.news.yahoo.com/s/afp/06122..._telecom_drink
14,000 driving-under-the-influence accidents, killed 707 people... and lobbying to increase penalties after a driver under the influence of alcohol killed three children in Fukuoka.
Oh yeah, the residential speed limit is 40km/h, and you are liable to huge fines if you speed.
Plus this page has some interesting information, too:
http://www.pref.ibaraki.jp/bukyoku/s...2demerits.html
Basically, if your driving causes a fatal accident, the laws are very strict no matter whether it was your fault or not. If dangerous driving, lack of license, fatigue, alcohol or drugs play a part in the negligence, there are serious repercussions in the shape of fines and jail time. The details also differentiate between drink-driving, the BAC threshholds, and driving under the influence.