The Altstadtbus runs between the Hauptbahn-hof and the Altstadt every six minutes for just €0.70, except Sunday. The bus transfer point is one block north of the Hauptbahnhof, on Albertstrasse. Tickets cost €1.70/2.30 for short/long journeys in the centre; strip tickets cost €5.60 for five rides (two strips per ride in town). An all-day ticket (€3.50 at ticket machines, more on the bus) is a better deal.
The Steinerne Brücke and much of the Altstadt is closed to private vehicles. Car parks in the centre charge from €1.20 per hour and are well signposted.
For a taxi, call 194 10 or 520 52.
Bikehaus (599 8808; Hauptbahnhof; bikes per day €9/6; 10am-7pm Mon-Sat) Staff here can help plan bike trips along the Danube and in other regions. It also has bike storage.