In saying that - let me give you some tips if you might be planning on renting a car and driving around for some of your trip. I'll cover some general road rules here, as well as some advice we have learned along the way.
First and foremost...
The driving side on Japan is the left. I was used to this, but some of my American friends who are used to driving on the right found it a little tricky to adapt to! You might have a few times when you use your blinkers instead of your windscreen wipers - totally normal!
There are toll booths - most highways are tolled roads.
Be careful where you park!
This is something we also learned the hard way. Make sure that where you're parking is actually a designated parking area. Sure, it might seem cheaper to just pull over on the side of a street somewhere rather than pay for a spot in a specific parking lot (Japan has LOTS of paid parking lots - it's usually pretty easy to find one) but it's a heck of a lot better to pay for a parking spot than having to pay a parking fine. The standard parking fine in our local area is 15,000 yen, or about $150 US, give or take for the exchange rate. Not something that you want cutting into those vacation funds!
Highway rest areas in Japan are actually GREAT places to stop.
Sparkling clean bathrooms, plenty of shopping and souvenir options, and delicious regional food specialties to sample? We love Japanese highway rest areas for so many reasons, and those are just a few of them. In a lot of other places around the world, highway rest areas have a bit of a sketchy feel to them - but not here, they're incredible! Check out some of the cool ones that we have passed through here!
Watch what you drink!
Pay attention to signage - map your route before you head out or use GPS.
Signage often hasn't been what I expected here. You will find most things are in both English and Japanese, but it's not always easy to follow or it sneaks up on you really quickly! Case in point: My husband and I were used to highway exits back home that told us what attractions would be found by taking that exit - or even highway signs that told us how many kilometres or miles to our destination, so we could gauge it that way - you don't see those here though, or at least in the experiences we've had on the roads!
In saying that though, driving in Japan allows you to really get off the beaten path a bit - and also you're not bound to timetables for public transportation - you're free to spend as long or as little in a place you want to. Also, the spectacular views you can see are worth it alone - like this quick snap I took out the car window (I was the passenger, don't worry!) when my husband and I passed through this toll booth near Mt Fuji.
Odigo has a great offer with Times Car Rental right now, where you can get 10% off a car rental booking - check it out at the link here if you're interested!