The transportation system you will probably make the most use of during your stay here is the VRR, the German acronym for the Rhine-Ruhr Transportation Association. This is a network of 28 local transportation companies and the German railway (Deutsche Bahn), which have agreed to a common ticketing structure. The major exceptions are the cities of Cologne and Aachen, which have not joined the VRR but have a separate pricing system when you buy a ticket that crosses into VRR territory.
The public transportation network in the Rhine-Ruhr region is extensive and includes streetcars, buses, underground and surface rapid-transit trains. The VRR website (www.vrr.de) has multi-lingual information and offers a trip planner and network maps, as well as articles on special events in the area and how to get to them.
The fastest way of traveling within the city of Düsseldorf is the U-Bahn, which is the short form of Untergrundbahn, or underground train. There are seven U-Bahn lines covering a large swath of Düsseldorf, particularly the central, northern and western areas. The lines are designated by numbers, as in U70, and go all the way up to U79. A similar designation by number is used for the S-Bahn as well (see below). The U-Bahn is by far the most popular method of getting around the city, as the trams are almost always crowded during the morning and evening rush hours.
The S-Bahn, or Schnellbahn (fast train), covers much of the area the U-Bahn misses but also runs over some of the U-Bahn territory. It also serves many outlying areas, including Dortmund, Essen, Cologne and Wuppertal, to name just a few. The S7, for example, will take you to the Düsseldorf International Airport, as well as the city of Solingen.
Straßenbahn is the German word for streetcar or tram. It is for those travelers who want to travel some stretch not covered by the U-Bahn or S-Bahn, or who have the time and inclination to take the scenic route. It covers a number of areas within the city, with several lines connecting Düsseldorf with other cities in the Ruhr area. The Straßenbahn in Düsseldorf is designated by a three-digit number starting at 701 and going up to 719.
The local bus system also takes you to areas that the rapid-transit trains do not. Some of them stop at every street or so, bringing you very close to the door of your destination. However, buses are also the slowest mode of public transport, as they must operate on the same streets as private cars and trucks. In the wee hours of the morning, buses are the only form of public transportation available. A number of special night buses ply the streets between midnight and dawn, designated by an 'N' before their number. These buses do not service regular bus stops. To find out which stops these buses use, look for signs with "NachtExpress".