Glasgow's city centre is compact and easily explored on foot, but public transport will be needed to reach some of the major attractions, which are farther out. The integrated transport network includes a reliable but confusing bus system with connections to the underground and train network. Some routes operate limited services throughout the night. The simple underground system, also known as the Clockwork Orange, has two circular routes that are easy to understand; this is the best way to get between the city centre and the West End. The suburban train network is fast and efficient. Taxis are readily available and provide excellent, if fairly expensive, service. A car is not necessary in the centre, and it is often easier to get around using public transport. Car users can make use of the park-and-ride system at underground stations outside the city centre.