The influence of public transport supply on private car use in 17 mid-sized Swedish cities from 1997 to 2011

We analyse the impact of increased public transport supply on private car use using micro data on individuals from 17 mid-sized cities in Sweden. The data is obtained from Swedish administrative registers (tax and odometer), which exists for all Swedish adults and cars, and information of public transport supply, namely bus kilometres supplied. In a description of the data we see that that the increase of private Vehicle Kilometres Travelled (VKT) per inhabitant stagnate in the sample cities towards the end of the period 1997-2011. Our hypothesis is that changes in the supply of public transport is the main cause for this stagnation. The probability of owning a car and the demand functions for VKT are estimated. The principal finding is that private car use is reduced by increased supply of bus kilometres with an average elasticity ranging from -0.01 to -0.04. This effect is larger in peripheral areas and in larger cities. In small cities the effect is almost nil. We conclude that public transport has an effect on the private VKT of inhabitants but that the impact is relatively small and cannot be the main cause for the stagnating increase of private VKT per inhabitant in the sample cities.