Скачать или смотреть Japan's ETC (Electronic Toll Collection System) - ETC高速道路 - Japan As It Truly Is

A quick look at the ETC - no more waiting in lines and poking around for exact change for Japan's toll roads. Your car has an ETC (Electronic Toll Collection) transceiver and card, and your credit card is billed later. About 30% of traffic jams are created by the lines of paying tolls, so this is one quick way to deal with it.
You'll need 2 things for it in your car - the card reader and the card. If you don't get a reader with it when you buy it, you can get one in an auto parts store (typically ¥10,000-¥15000). You then need to get the card and register with it, connecting it with a bank account or credit card, and then have the reader installed. Once that is done, you can use the card in any car with a reader (rental car, friend's car etc).
Be sure to use the purple ETC lane at the on and off ramps, and you should only be going about 20 kph passing through.