The excellent public transport system in Austin provides cheap
public buses and vans that cover all neighbourhoods, downtown and
the university campus for a flat fare. Transfers between buses are
free and valid for three hours. The Armadillo Express, known as
'the Dillo', provides free trolley rides through the historic
downtown area. There is also a free Yellow Bike Program that makes
bicycles available to the public - yellow bikes can be picked up
anywhere, ridden to one's destination and then left for the next
rider. Taxis can be expensive and are best ordered by phone,
although they are on hand outside most downtown hotels. Driving in
Austin can be very confusing, with a lack of clear east-west routes
through the city centre and the fact that locals tend to refer to
highways by unofficial names. The city centre can become congested
at rush hour.