Research projects

In the context of climate change, the transition towards more sustainable mobility and transport systems has become a prominent topic in academic, public, and political debate. The transport sector plays a particularly important role in meeting national climate targets. At the same time, the transport sector has achieved only limited emission reductions compared to other sectors. Public transport is widely regarded as the backbone of a sustainable local and regional transport system and still offers considerable untapped potential for reducing transport-related emissions. As part of the German government’s energy relief package, the nationwide 9-Euro Ticket (9ET) was introduced for three months in the summer of 2022 as both a transport and social policy measure. This was followed by the introduction of the Deutschlandticket (DT) in May 2023. Unlike the 9ET, however, the DT is offered as a subscription and at a substantially higher price (initially €49 rather than €9 per month).

This project investigates the extent to which the 9ET and the DT contribute to more environmentally and socially sustainable mobility behaviour. Changes in travel demand are examined within the interplay between the spatial environment, individual mobility-related attitudes, and daily travel behaviour. The findings are discussed in relation to spatial context effects, residential self-selection, and reverse causality. The aim is to assess both the short- and long-term effects of the introduction of the new ticket schemes – the 9ET and the DT – on daily mobility.

The analysis draws on existing quantitative panel data collected in three waves, partly using retrospective questions, to capture mobility behaviour at five points in time (Wave 1: 9ET; Wave 2: no nationwide ticket scheme; Wave 3: DT at €49 per month). The survey was conducted in five neighbourhoods in the eastern Ruhr region that differ in terms of their spatial characteristics and public transport accessibility. As part of this project, an additional fourth wave was conducted in 2025 (Wave 4: DT at €58 per month) to investigate long-term effects.

The empirical analysis is organised into three main work packages focusing on mobility-related attitudes, season-ticket ownership, mode use, and changes in these outcomes. Both descriptive methods and advanced multivariate methods are applied. To support the interpretation of the findings and the development of conclusions, the empirical results are presented and discussed in an expert workshop.