You guys are quick to speak before knowing the facts. There are parts of Japan where industrial estates which aren't used at night are opened up to allow for street racing, which the cops allow because it keeps the dangers away from populated areas. The industrial estates are typically built on large man-made islands, some of which are originally offshore naval fortresses, in the Tokyo/Yokohama bay area and connected by bridges and tunnels (for example the bridge you see in this video). When dawn breaks, the cops come to peacefully clear off the remaining few who are still awake before the working day starts.
The only other traffic is lorries travelling to/from the very few overnight factories, taxis ferrying tourists (like myself) who go to watch the racing, and burger vans providing food. This practice has been going on for years, anyone who does drive in the area knows to avoid the outside lane (if the drivign laws are the same as in the UK you're only allowed in that lane if you're overtaking anyway, and lorries aren't allowed there at all), specially for the racers to use. Chances are other "innocent motorists" travelling around here are other racers or spectators, simply not driving as fast.
Furthermore, you'd be amazed at how civil these people are. These aren't your standard chavs hanging around mcdonalds. When my taxi arrived in the area, driving around looking for the main hangout area, a dodge viper was drifting down the lane, he came to a dead stop at the junction, even though it was his right of way, let the taxi pass, and carry on. the whole social gathering is almost professionally organised, and the people i spoke to had good jobs and were actually surprisingly middle-aged, putting time and effort into tuning and styling their cars was their livelihood, not just some hobby of unemployed people trying to pull girls using their rich dad's money.
