It would take you thirty seconds to find this shit out with your AI of choice but, Jesus Christ, you’re getting bodied in the comments already.
So, here you are. Loads of research you won’t read because you’ve “done your own research” – note that having an opinion isn’t quite the same. As I mentioned I went to the Minister with a folder full of this shit ten years ago. I didn’t turn up with a stupid grin and a tree hugger badge. Massive savings to the economy directly, massive savings due to the improved health-related outcomes and, on top of that, if you take things like bus lanes and cycle lanes actually seriously it reduces congestion. The ALTERNATIVE (the one proposed by the Roads Service in Northern Ireland) is BUILD MORE ROADS – which is what happens when you stick 600 road engineers in a building and ask them for solutions.
Most objections to PT improvements tend to come from people who don’t really want the poors to get benefits. But even Phony Stark thinks mass transit is a smart idea (as he reinvents trains and buses for the techbros)
With the burden of proof on my side resolved, you can see why I’m supporting these moves. When your mum is driving you to your next appointment, she would have less traffic.
But here we are. Examples of how public transport did all of the things I said – and not just congestion. Nice of them to keep researching it to provide up to date data.
Public transport & traffic congestion / traffic flow
Anderson, 2014 – Los Angeles transit strike “natural experiment”
Reference: Anderson, M. L. (2014). Subways, Strikes, and Slowdowns: The Impacts of Public Transit on Traffic Congestion. American Economic Review, 104(9), 2763-2796.
What it does: Uses a multi-week LA transit strike as a shock and measures what happens to congestion when transit is removed.
Key findings: The strike increased peak-period delays by about 47%, implying that operating LA’s transit system reduces traffic delays by billions of dollars per year.
Beaudoin, Farzin & Lin Lawell, 2015 – Literature review on transit & congestion
Reference: Beaudoin, J., Farzin, Y. H., & Lin Lawell, C.-Y. C. (2015). Public transit investment and traffic congestion: A systematic review of the empirical literature. Transport Policy / Transportation Research family.
ScienceDirect
Key findings: Reviews empirical work on how transit investment affects congestion and air quality. Concludes that PT can reduce congestion, especially in dense cities and congested corridors, but effects are context-dependent (land use, road pricing, etc.).
Beaudoin & Lin Lawell, 2016+ – Theory & empirical work on congestion relief
Reference: Beaudoin, J., & Lin Lawell, C.-Y. C. (2016). The effects of public transit investment on congestion, auto travel demand and air quality. In The Economics of Transport (chapter).
clinlawell.dyson.cornell.edu
Key findings: Shows that transit investment can reduce car travel and improve air quality; congestion relief is significant where transit is competitive in time/cost and road networks are already saturated.
Monetary valuation of congestion relief from PT
Reference: Comparative review of “Evaluating the Congestion Relief Impacts of Public Transport in Monetary Terms” (2025 working paper / review).
ResearchGate
Key findings: Summarises international evidence that PT absorbs peak-hour demand, increases overall network capacity and reduces congestion, and converts these effects into monetary values for cost-benefit analysis.
Tallinn, Estonia – the classic free PT case
Cats, Reimal & Susilo, 2014 – Before/after evaluation
Reference: Cats, O., Reimal, T., & Susilo, Y. (2014). Evaluating the Impacts of Fare-Free Public Transport Policy: The Case of Tallinn, Estonia. Transportation Research Record, 2415, 89-96.
repository.tudelft.nl
Key findings:
Fare-free PT increased boardings, especially in lower-income districts (upwards of ~10% in some areas).
It improved mobility for unemployed and low-income residents.
Chen, 2014 – Mode choice under Tallinn’s free PT policy
Reference: Chen, X. (2014). How the free public transport policy influences public transport mode choice: The case of Tallinn, Estonia (Master’s thesis).
DIVA Portal
Key findings: Fare-free policy changed perceptions of PT and increased its use, but price alone was not enough to induce large numbers of drivers to switch without parallel measures (parking, service quality, etc.).
Dunkirk (Dunkerque), France – free buses + network upgrade
Urban Mobility Observatory / French studies
Reference: EU Urban Mobility Observatory. (2019). Free public transport in Dunkirk, one year later.
EU Urban Mobility Observatory
Key findings:
After introducing free bus travel and redesigning the network (September 2018), bus ridership increased by 65% on weekdays and 125% on weekends.
A follow-up study reported a “significant contribution” to reducing private car use; about half of new bus users previously drove for the same trips.
Local evaluation & surveys
Reference: Observatoire des villes du transport gratuit – Dunkirk study on young people & mobility.
obs-transport-gratuit.fr
cbwmagazine.com
Key findings:
Many respondents reported using the bus instead of a car; a small but non-trivial share sold a car or avoided buying a second car.
Reported benefits: better access to jobs and social activities, reduced transport costs, perceived improvement in air quality and urban environment.
Germany’s 9-Euro Ticket – deep discount nationwide
Klotz et al., 2024 – Highway traffic response
Reference: Klotz, P. A., et al. (2024). The Impact of Public Transport Subsidies on Highway Traffic: Evidence from Germany. Working paper.
EconStor
Key findings:
The temporary 9-Euro Ticket (summer 2022) led to a more than 18% decrease in highway passenger traffic in Germany during the policy period.
Public transport demand increased by ~44%, with survey evidence of some substitution from car to PT and reduced particulate pollution.
Effects on car traffic were significant but mostly temporary, fading when the ultra-cheap fare ended.
UITP, 2020 – “Full Free Fare Public Transport” policy brief
Reference: UITP (International Association of Public Transport). (2020). Full Free Fare Public Transport (Policy Brief).
UITP
Key findings:
Across multiple free-fare cities, ridership tends to rise substantially.
However, reductions in car use are “quite limited” in many cases; a lot of the extra PT use comes from walking/cycling and induced trips.
Where there is modal shift from car, potential benefits include improved local air quality, road safety and noise reduction, but capacity and funding constraints can offset some gains.
Wider co-benefits (health, emissions, equity)
Built environment, active travel & PT – health + congestion co-benefits
Reference: Smith, M., et al. (2017). Systematic review of built environment effects on physical activity and active travel. Health & Place, 43, 287–299.
PMC
Key findings: Replacing motorised trips with active modes and PT reduces congestion and emissions while improving physical activity and public health.
Low-carbon transport in cities – air quality & health
Reference: International Transport Forum / OECD. (2025). Health Impacts of Low-Carbon Transport in Cities: Evidence for Decision-Making.
ITF OECD
Key findings:
Shifting from private cars to PT, walking and cycling cuts greenhouse gases and improves air quality.
Associated reductions in premature deaths and chronic disease make PT expansion highly cost-effective.
Fare-free PT & social inclusion
Reference: Štraub, D. (2025). Re-examining fare-free public transport for greater inclusivity: Evidence from Brazil’s student fare-free law. Case Studies on Transport Policy.
ScienceDirect
Key findings: Shows how fare-free schemes for low-income students improve educational access and social inclusion, illustrating non-traffic benefits of free PT.