Highway is the fifth stage in Hill climb racing. It costs 125,000 coins to unlock
Highway is one of the most popular maps in the game because of how easy it is to go far in it. It is mostly flat with some gradual hills, when you get to about 2000 meters, there will be some steep hills, that you might need to use a booster for. While the level itself is easy enough, the real challenge is fuel efficiency. The gas canisters get farther and farther apart as you progress in the level, which tests your fuel capacity and efficiency. If you are fast enough or have a good enough fuel tank, you can go practically infinitely. The Race Car is amazing in this level because it can go incredibly fast with the flat features in the level, but its fuel capacity is low and it can only go around 6000m. Later in the game, the Super offroad gives the same performance as the race car but has a dedicated fuel upgrade, so it has much better fuel capacity.
This stage has many coins in it, and past a certain point all of which is 500 coins. It is easy to earn upwards of one million coins per run. However, if you want to actually get a lot of coins, you should go to Moon as you get a lot of airtime.