A service station is a petrol station or a gas station ... a place where people fill their vehicles with fuel, pick up chips and chocolate bars for themselves, and use the toilet. Some have restaurants and occasionally the larger ones will have showers (something to keep in mind while you are on your tour). They are usually located throughout cities, but especially around the edges of cities on the main roads in and out of the cities. They go by the names BP, Esso, Mohawk, Shell, and several others.