About Japanese Traffic

Stay in the Left Lane
Japan is one of the few countries where the cars are driven on the left side of the road. This confuses some people, especially when turning at a corner.
Not only that, general Japanese cars come with the steering wheel on the right. Make sure you find out which lever is for turning signal and wipers before you start driving. You do not want to find out in the middle of the highway.

Beware of Narrow Streets
You may be from a country with big cars and wide streets. However, you are now in a country where the population per area is 338 persons/km2 (or 875 persons/mile2). This should make it clear that there is lots of traffic. Bicycles would be on the road with your car. Be aware...you are surrounded.

This is a World of Metrics
We are not too worried, because all of the cars and meters will be switched to metrics before driving on the road. However, keep in mind that you are driving in metrics. The idea of speed you feel would be significantly different compared to what you see.

Difference in Gasoline Service Stations
Unlike some countries, single Japanese service stations for gasoline may be self-service or full-service. No station provides both options. Make sure you find the right one for yourself when looking for a place to refuel.
Another note, most of the gas tanks (or fuel doors) on Japanese cars are on the left side, with some exceptions. Make sure you know which side it is on before pulling in.
(Note: In case you forget which side the gas tank is in your car, check the little gas indicator on your dashboard. There should be a tiny arrow next to it. The arrow points to which side the gas tank is on your car.)

Preparing for snow
If you live in an area where you get continuous snowfall, stud-less winter tires or snow tire chains are almost always a necessity. In Tohoku (where Misawa Air Base is located), Hokkaido and the Chubu Area on the coast of the Sea of Japan, there is much snow in winter. In other areas excluding Okinawa, it sometimes snows heavily. It is best to check the weather forecast before driving in the winter time.