New simulation study examines impact of self-driving services on public transport in Gothenburg

• Transport model by PTV Group to analyze various future AV scenarios
• Increased traffic possible despite reduction in overall number of vehicles
• Understanding impact of AVs enables sound decision-making by authorities

Karlsruhe/ Gothenburg, 2 May 2022. How will the advent of autonomous vehicles (AVs) and new mobility trends affect public transport systems and the traffic situation in cities? A new report based on a simulation model provided by PTV Group, explored potentials and risks of electric, shared, and self-driving vehicles in the Swedish city of Gothenburg.

The aim of the research was to analyze how self-driving vehicles will affect the city by modelling different scenarios, using Gothenburg’s multimodal modelling platform in PTV Visum software. The project brought together researchers and traffic analysts from Trivector and the Swedish knowledge centre for public transport, K2. In the virtual environment of PTV Visum, the researchers examined numerous possible developments. They focused on two forms of AV usage: car-sharing, where people use self-driving services privately, like today’s cars; and ride-sharing, where AVs are shared with other passengers, who have a similar destination.

The researchers looked at different scenarios: For example, what happens if 33% of today’s car trips shift to AV ride-sharing? What effects occur if 100% of people shift from private cars or public transport to car-sharing or to shared, self-driving services? The project team analysed different parameters such as travel times, number of vehicles and vehicle mileage.

More AVs is not less traffic

The simulation results show that an increase in the use of self-driving vehicles does not automatically lead to less traffic, as often predicted. The total number of vehicles in the traffic network can vary without reducing the vehicle milage.

With shared self-driving vehicles, the total number of vehicles in the traffic system might be significantly less, but each vehicle drives more.  Several of the simulated scenarios resulted in an increased traffic volume, despite a reduction in the overall number of vehicles.

Here are some other main findings of the study:

• The transition to AV car-sharing leads to a 25-30% higher traffic volume than the transition to AV ride-sharing
• If people switch from private cars to electric, self-driving ride-sharing options, traffic volume decreases by up to 6%. The shift from today’s private cars to AV car-sharing makes traffic rise up to 15%
• If in addition to today’s car users, public transport users switch to AV services, traffic increases in both the car-sharing and the ride-sharing scenario.
• The transfer from today's car traffic to AV ride-sharing and AV car-sharing reduces the volume of vehicles on the road by up to four-fifths of today’s volume. This would likely reduce the need for parking spaces and purchase of new vehicles

Scenario analyses enable sound decisions

Kim Örn, PTV Group, explains: “There are many uncertainties and open questions on how the autonomous future will develop. For instance, if AVs will increase our desire to travel more? How quickly society will adopt them? Digital models allow us to simulate in multiple combinations of assumptions which produce a range of future outcomes. The range of results enables planers to understand which assumptions have a greater or lesser influence on the outcome, stakeholders can make decisions with increased confidence.”

“Our work clearly shows that self-driving vehicles will have a major impact on the transport system and if applied correctly, they will create economic, ecological and social sustainability benefits. But we must continue to develop our understanding of the concept through simulations, test beds and by understanding people's attitudes” say Fredrik Larsson, Head of analysis at the Urban transport administration at the city of Gothenburg and Lennart Persson Head of Trivector Gothenburg.

The way new self-driving services will be designed, and how well they are integrated into public transport, will have a major impact on cities and the traffic situation in particular. The report points out the importance of knowing and understanding possible effects of new mobility services in order to minimize negative impact. The researcher conclude that planning, legislation, and regulations must be aligned around AV ride-sharing services to ensure that AVs contribute to a sustainable mobility ecosystem in the future.

The entire report can be found online (Swedish only): https://www.drivesweden.net/sites/default/files/content/bilder/slutrapport_eldsjal_k8.pdf