Urbino is small and almost entirely walkable, though the cobbled streets are steep — sturdy shoes are non-negotiable. From end to end the historic centre is no more than 700 metres.
There is a useful escalator running from the Borgo Mercatale car park up to Piazza della Repubblica, which saves the worst climb from the bus station if you're arriving with bags.
Driving inside the walls is restricted to residents. Local buses (Adriabus) connect the centre to the train stations at Pesaro and Fano.