In the big cities the major forms of transportation are the bus or subway. There are also many taxis in the cities. There are two kinds of taxis, the silver-grey (regular) and the black (deluxe or jumbo). The regular taxis start with their meters at 1,600 won (about US$1.23) while the deluxe start at 4,000 won (about US$3.10). This gives you a certain amount of time. The meter then begins to add for any extra time. The deluxe or jumbo taxis are nicer cars. The only difference I could see was that one cost twice as much as the other, so we avoided using the black taxis.
Travel between the cities is by either bus or train. The photo at the left is the Inchon Bus Terminal. As you can see they are quite modern buildings. Some bus terminals in the big cities are older.

The trains are the cheapest way to travel between cities. Terminals like in the photo above are in the smaller towns.
Left: Inchon Bus Terminal

There are toll plazas on the highways. Hyundai is the most common car and bus in Korea. The car above is a Daewoo Matiz, a very small car.

In Korea, there are all types of vehicles, including pickups and big semi-trucks, but most of the trucks are like the one above.
There are many islands around Korea with ferries being used for travel between them.