Here is the excess capacity in the urban transport system
There is surprisingly good availability of free traffic space in Stockholm according to a report from CESC, Centre for Sustainable Communications, developed on behalf of the Swedish Transport Administration.
Cars are in average parked 96 percent of the time and have an excess capacity on average of 3.8 passengers when in use. In addition the traffic congestions occur only on a very small part of the road network. This paper shows, in contrast to what is customary, the idle capacity in urban traffic and how it could be utilized differently.