News & Views

For many people, owning a car isn’t just about getting from point A to B. It represents freedom, convenience, and sometimes even a status symbol. In many places, cars remain the go-to option because public transport systems are unreliable, slow, or simply don’t reach where people need to go. With car ownership on the rise globally—and its environmental and societal consequences becoming increasingly severe—understanding the potential of public transport as a solution has never been more important. Rail-based systems are often touted as effective tools for curbing car use. However, research remains inconclusive on whether they lead to a long-term reduction in car ownership, especially in the UK context.

To investigate this, I conducted a study as part of my master’s dissertation and dived deep into Manchester’s Metrolink system as it represents one of the UK’s most prominent light rail networks outside of London, offering a unique opportunity to isolate and evaluate the effects of a rail based public transport intervention on car ownership.

The Metrolink has expanded in phases since it first launched in 1992. The goal was to offer a reliable alternative to driving, reduce congestion, and improve air quality. But has it actually led to fewer people owning cars? To find out, I studied census data from 2001, 2011, and 2021, looking at how car ownership levels (car per household) changed in areas (LSOA level) where the Metrolink was introduced versus areas where it wasn’t.

How was the study conducted?

To analyse the Metrolink’s impact on car ownership, I used the Difference-in-Difference (DiD) method to compare changes in car ownership in areas affected by the Metrolink (treatment group) with areas that remained untouched by the tram expansion (control group).

The study also accounted for several confounding variables that could be impacted by the Metrolink and consequently impact car ownership rates. These included:

• Population density – More densely populated areas tend to have lower car ownership rates.
• Household size – Larger households are more likely to own multiple cars.
• Social grade – Higher-income households often have higher car ownership.
• Accommodation type – People living in apartments or rented accommodation are generally less likely to own a car.

By incorporating these variables into a linear regression model, I was able to better isolate the impact of the Metrolink itself, rather than just changes due to broader demographic trends.

What do the numbers say?

The initial analysis, which didn’t account for other variables, showed no statistically significant impact of the Metrolink on car ownership. However, when adjusting for confounding factors through the linear regression model, a different picture emerged.

After accounting for population density, household size, social grade, and accommodation type, it became clear that the Metrolink did reduce car ownership, though the effect varied across different phases:

• Phase 1: Car ownership dropped by 6% in affected areas.
• Phase 2: Car ownership dropped by 10.9% in affected areas.
• Phase 3A: Car ownership dropped by 3.8% in affected areas.

The bigger picture

So, does better public transport reduce car ownership? The answer, based on this study, is yes—but with caveats. The Manchester Metrolink has played a role in reducing car ownership, particularly in certain areas. However, it’s clear that public transport improvements alone won’t completely replace the car. A more comprehensive and coordinated approach—including urban planning, policy changes, and investment in alternative transport modes—is essential for cities looking to reduce car dependence in the long run.

International studies highlight that reducing car ownership requires a combination of measures, such as:

• Congestion charges – Discouraging driving in city centers.
• Improved cycling and walking infrastructure – Making alternatives to cars more attractive.
• Policies that limit parking availability – Reducing incentives to own a car.
• Affordable and well-connected public transport – Ensuring that switching from cars is a convenient option.

Ultimately, while better public transport is a step in the right direction, it’s not the silver bullet. However, if combined with the right policies, cities can encourage more people to leave their cars behind and embrace more sustainable travel options. If we want to create sustainable, less congested cities, it’s not just about making public transport better. It’s about making them the best choice.

ITP brings extensive expertise in delivering public transport projects and provides strategic advice to both public and private sector clients across the UK and internationally. Our work focuses on improving public transport systems to better serve local travel needs.

For more information on the Public Transport services that ITP offers, visit our Public Transport page or contact Denise Faber.