How transport policy shapes commuting patterns: The case of the Bratislava sub-urban area

We analyse the commuting patterns in Bratislava's fast growing sub-urban region with sub-optimally developed infrastructure. A standardized discrete choice model is used to estimate the demand for individual car transport as well as public buses and trains, and to obtain corresponding elasticities with respect to travel costs, times and income. We find a low rate of substitution between the available modes of transport. The direct price elasticity for public modes of transport is in accordance with the often-quoted rule of thumb of -0.3. Negative income elasticities of the demand for buses and trains, together with a low direct price elasticity for car transport can be hard to overcome when looking for a solution for the current traffic problems in the region. We use modelled demand to predict the effects of two recent draft policies - the new parking system in Bratislava city and the construction of highway D4R7. In the case of the first policy, we expect a massive reduction in car use due to increased costs for car commuters. On the other hand, the new highway would only have a limited impact on mode choice and could reduce the number of train commuters.