In Japan, all cars have to undergo a vehicle inspection called shaken every two years. The ostensible reason is to make sure each part of the car is in safe, working condition, but some motorists suspect the real reasons are to bilk additional streams of revenue from owners, as well as encourage them to trade in their current cars for new models, which can go three years before their first shaken.
The system does have one upside for enthusiasts. Since cars get officially inspected every other year, traffic cops in Japan aren’t nearly as zealous as their U.S. counterparts about issuing fix-up tickets for questionable modifications they spot on the street. This means that during the two-year period between shaken checks, you have a decent chance of getting away with illegal engine mods, non-compliant body kits, or awesome grey-area cat tail lights.