The Vienna U-Bahn is a rapid transit system serving Austria. Since its opening in 1978, the U-Bahn has played a vital role in connecting the city's diverse neighborhoods, cultural sites, and business districts. The five-line network covers 83.1 kilometers (51.6 mi) of route, serving 109 stations. Lines are designated by a number and the prefix "U" (for U-Bahn) and identified by a color on station signage and related literature. U-Bahn services run at intervals of two to five minutes between 05:00 and 01:00 during the day and up to eight minutes after 20:00. With modern facilities, punctual services and a focus on accessibility, the Vienna U-Bahn not only reduces traffic congestion but also contributes to the city's reputation as one of the world's most liveable and well-planned urban centres.