Density: the missing piece of the UK’s public transport puzzle?
Centre Cities
Increasing public transport ridership is not just about network coverage and fares – increasing density around stations underpins the success of other policies aimed at encouraging modal shift.
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Centre for Cities
As part of efforts to reduce carbon emissions and make progress on net zero targets, many UK cities have set ambitious targets to increase the share of journeys made on public transport. London, for example, is aiming to reach 80 per cent of trips made using public or active travel by 2041, Manchester 50 per cent by 2040, and Glasgow has set a target of reducing car vehicle kilometres by 30 per cent by 2030.

Gear shift: International lessons for increasing public transport ridership in UK cities finds that UK cities are starting from a lower base when it comes to the share of people commuting by public transport compared to similar-sized European cities. This disparity is particularly driven by large cities which have much higher ridership than UK cities.

Measures such as integrating and improving networks, prioritising public transport and simplifying fares, combined with policies such as congestion charging to dis-incentivise private car travel, can help to encourage modal shift, but the success of these policies and viability of networks is underpinned by density.

Why density matters

There are two main factors which determine how many people are within easy reach of a public transport network. The first, which tends to be more talked about, is the distance covered by the network. The second, which is where UK cities struggle compared to their European counterparts, is how many people live within this catchment area. In other words, the density of residents around public transport stops.

For example, by UK standards, Glasgow has a geographically large public transport network, in third place behind London and Birmingham in the UK in terms of the distance that can be covered in 30 minutes from the city centre. The city’s low density – 17.7 per cent of its residents live in areas with more than 6,000 residents per square km, lower than the UK urban average of 32.32 per cent – means that despite an extensive public transport network, fewer people are able to access the city centre than in cities with a smaller network but higher population density such as Turin or Seville.

Increasing the density around public transport stations, both existing and new, helps to maximise the number of people who can easily access the network. Given that research shows that passengers view time walking to stops, waiting or transferring as more onerous than riding a single mode of public transport, proximity to transport stops is a key factor in encouraging usage. The increased likelihood of congestion in higher density areas (caused by the greater volume of people to road space) also helps to make public transport the preferred mode of travel, particularly when effective public transport prioritisation measures such as bus lanes are in place.

How do we increase density?

So, to support effective and attractive public transport networks, cities need to recognise the role of density by planning for transport and housing together.

Lille, France, has successfully increased density and passenger numbers through transport-oriented development. Lille Metropole, which coordinates 95 municipalities in the city region, adopted an approach known as ‘Disque de Valorisation des Axes de Transport’ (DIVAT). This approach is a tool for local government to coordinate urban planning and transport provision with the aim of linking density and transport accessibility levels and is applied in 500 metre zones centring on major transport stops such as tram, metro and rapid bus stops. These zones are designed to help identify potential sites for development around transport routes, and there are recommendations for housing densities and parking minimums in place.

Using this approach, Lille redeveloped the deserted area around the suburban station of Armentières as an intermodal transport hub with commercial and residential space and active travel infrastructure during regeneration in 2006. Density increased to 39 residents per hectare, compared to 18 in the wider Lille Metropolitan Area. These changes were accompanied by the launch of intermodal ticketing and daily fare caps. This combination of policies resulted in an increase in passenger numbers from 3,300/day in 2005 to 5,000/day in 2012.

Cities in the UK should implement similar joined-up plans, as is already the case in the London Plan which aims to add an additional 20,000 homes around stations in the capital over the next decade. Elsewhere, local authorities should use their powers to implement Local Development Orders for mid-rise housing around new and existing public transport stops.

Densifying can help generate additional revenue

As well as increasing the number of people who can easily access a public transport network and helping to create a more efficient network, densification around public transport can be a source of revenue to fund further development of the network.

In Hong Kong, the city’s transport authority can develop the land around new stations, with the revenue raised from this being used to fund the system. In 2019, for every pound of ticket revenue, a further 60p came from property rental or management or commercial business in stations. There are examples from less dense cities, too. In Montreal, a land value capture scheme is expected to generate CA$600 million towards the CA$6.9 billion budget to expand the city’s Reseau Express Metropolitan (REM) light rail. In this scheme, a tax of CA$8 per square foot of floor area is levied on developers for all new construction within a 500m – 1000m radius of REM stations.

And there is already precedent for this kind of revenue generation in the UK. By borrowing against anticipated business rates receipts in the area around the development in a process known as tax incremental financing, the Greater London Authority was able to fund the £1 billion Northern Line extension to Battersea Power Station.

Density shouldn’t be an afterthought for cities looking to encourage modal shift and improve their public transport offering. Instead, cities should focus on density as a catalyst for more efficient transport networks and a key factor in the success of other policies aimed at increasing ridership.