A case for reducing highway construction in urban extensions

How can we avoid building roads in Bradford to 'unlock' new development? When creating a masterplan and vision for urban extensions, potential for sustainable transport mode share is often squandered by the classic predict and provide process.

This case study is a part of the LGA's Decarbonising Transport Action Learning Sets (ALS) programme


How can we avoid building roads to 'unlock' new development?

When creating a masterplan and vision for urban extensions, potential for sustainable transport mode share is often squandered by the classic predict and provide process. Urban fringe developments often have poor transport outcomes. In our case, an Urban Extension will be ‘unlocked’ by the provision of a new road link. We used the ALS process to explore how we could evidence sustainable transport investment to unlock new development instead, to minimize new highway construction and avoid the emissions that a highway-focused plan would lead to.

What is the challenge? 

In the emerging Local Plan for south-east Bradford, there are plans to build a new Sustainable Urban Extension of at least 1,800 homes. Two major site promotors have options for a significant area of land beyond the proposed sites for 1,800 homes; and if all options are exercised in this area, there could be up to 3,000 new homes built on greenfield (green belt) land. The Local Plan has proposed an urban extension in this location is considered the most suitable and sustainable option for delivering the district’s housing requirement, due to the reduced impact in comparison to other areas explored. The urban extent forms a key part of the Council’s balanced land supply approach, combined with the prioritisation of brownfield sites within the urban core of the City of Bradford and major towns such as Keighley.

In order to facilitate new housing in this location, the current solution would see a highway access route constructed to the east of Holme Wood, connecting into existing highways at either end, and providing a through route for north-south traffic in this area. The strategic case for the highway intervention is based on reducing traffic on parallel routes, network resilience and supporting housing growth. The total scheme cost would be £43-64 million, with part of the cost being met by developers.

The incumbent approach is problematic, as conceiving an urban extension around an orbital highway access route could lead to the following issues:

  • Low-density development, with fewer local destinations and less of a mix of uses, encouraging longer trips by car.
  • Longer-distance trips encouraged as opposed to short-distance trips.
  • Trips oriented towards edge-of-town or out-of-town destinations rather than city centre, which have easier parking and fewer public transport options.
  • Developers likely to justify more parking, which will encourage greater car ownership and use.
  • Longer public transport journey times to the city centre, discouraging use and increasing operational costs.
  • Overall increase in highway capacity would lead to induced demand, including for through trips.
  • Any greater highway capacity constructed than the strict minimum necessary would incur greater carbon costs from construction and maintenance.
  • Highway access would be attractive to owners, leading to greater car use.
  • Walking and cycling links to nearby destinations could be ill-conceived or unattractive.
  • Developer contributions would be used up in funding the highway access route construction, leaving less money to be spent on sustainable transport initiatives if the development is to remain viable.

These issues would each lead to greater carbon emissions from transport.

It would be more carbon efficient for embedded and operational carbon if the urban extension could be enabled using means that avoided these issues. An alternative concept for South East Bradford could be based on a reserved right of way for buses on the main local radial corridor, offering rapid and reliable journey times into the city centre. Highway construction would be limited to access only, with no through route element. Better public transport on the corridor would encourage mode shift on a strategic level, reducing the need for further strategic highway interventions.

There are many decarbonisation benefits arising from the alternative concept:

  • Trips encouraged towards the city centre, which is better served by public transport.
  • High quality public transport service is provided from the outset, encouraging use over car.
  • The site is more permeable by sustainable transport (bus, cycle and walking) than by car, encouraging the use of sustainable transport.
  • Highway construction and maintenance requirement is minimised, avoiding these carbon emissions.
  • There is unlikely to be induced private vehicle demand from potential through-journeys.
  • Developer contributions can be used to secure public transport service without affecting viability.
  • Lower car mode share should allow for reduced parking requirement, enabling the development to be more viably built out at greater density.

The alternative concept also offers other benefits:

  • Active travel would be encouraged through stronger links to existing development.
  • Air quality in the area and Tong Valley would be improved when compared with the base concept.
  • Access for Holme Wood residents to nearby green space and woodland would not be impeded.
  • Existing and future residents would be less affected by traffic noise and vibration.

A path to pursuing the improved bus scheme has been found through City Region Sustainable Transport Settlements (CRSTS) funding. However, the alternative concept faces challenges in implementation as this path is more ‘decide and provide’ than the traditional ‘predict and provide’. The main challenge is making the concept seem acceptable to the different parties involved:

  • Highways and Planning Authorities
  • Department for Transport (DfT)
  • West Yorkshire Combined Authority
  • Planning Inspector
  • Land Promotors and Housing Developers
  • Prospective Owners
  • Existing Residents

As a result of the action learning set programme what actions will you now take to address the challenge? 

The challenge of making the alternative concept seem viable was brought to the ALS programme. The discussion covered the following:

  • Legacy highways schemes should be reappraised in the light of climate emergency. Local authorities need to move away from latching on to schemes.
  • What are other places doing that can encourage us to do things differently? Can we use examples from e.g. the Netherlands to sell the concept of reduced car neighbourhoods?
  • Would a solution be to advertise this as new and pioneering development? Distinctive promotional activity could help convince partners of the value of pursuing the alternative concept.
  • Looking at an Area Action Plan for the area could formalize the concept more. A consultation exercise could help shape proposals for this area to formalize the alternative concept.
  • What are the objectives of the road scheme? If these were re-appraised, then a different solution may be reached.
  • Is the urban extension needed? Could alternatives be looked for elsewhere that would have less of an impact?
  • What levers do you have to pull to affect change? Would DfT help in their capacity of being interested in pilot schemes?
  • Can we envision what the housing development will look like if it comes forward with a road? Being able to visualize the difference between the two concepts could help decision-making and be a useful tool in convincing partners.

As a result of the ALS programme, the council will engage through the Design Code work to promote a less highway-dependent urban form. This can be used to create materials to show how the development could be brought forward in a more sustainable way.

The council will explore through Faithful + Gould, who have been appointed to build the strategic case for intervention on the A650 corridor and South-east Bradford Access Route, to show how ‘Sustainable Transport Corridor’ interventions can be used to support the new development. Through this case-making, a WYCA Carbon Impact Appraisal can take place to examine the relative impacts of the two concepts, to aid in understanding.

There will be opportunities to explore DfT support for the alternative concept through that organisation’s involvement in the MRN funding round and in CRSTS.

What will be the impact? 

Adopting the approach outlined above should result substantial carbon savings for a future urban extension to be quantified through the Carbon Impact Appraisal process. Enabling the same or greater quantum of housing to come forward with less highway infrastructure should enable savings that can be re-invested in design quality and sustainable transport and will spare long-term expenditure on maintaining the highway.

If successful, this could set a precedent for application in other areas.

How will you look to sustain the approach in the long term? 

The processes can be maintained in the long term:

  • By taking the concept forward through Design Code work, producing a permanent document which will keep its reference value.
  • By taking the concept forward in work led by Faithful + Gould.

Lessons learned 

The ALS programme was useful in exploring the challenge in a collegiate atmosphere. However, the choice of topic was perhaps too big and complicated to address in the short timescales allowed. In particular, the interaction of urban extension with new road construction is difficult to navigate in conceptual terms, as the case for each is dependent on the other.