Smarter Cambridge Transport

Railroading decisions on busways and car parks

The Greater Cambridge Partnership (GCP) has published a 617-page agenda pack with references to reports comprising thousands more pages. At four-hour meetings, the Joint Assembly and Executive Board will consider officers’ recommendations to proceed with three busway-and-car-park schemes, budgeted to cost £340 million. For most of the councillors on those committees, these will be the first decisions they will make for the GCP.

Is this the way to make good long-term decisions? Or is GCP railroading inexperienced councillors into agreeing to proceed with environmentally damaging and demonstrably unnecessary projects?

All three projects are based on a false premise, expressed in the independent audit of one of them: “The [Cambourne–Cambridge scheme] remains the only means of increasing capacity on the A1303/A428 corridor and addressing the public transport travel needs of the growing population.”

There are in fact two ways to increase transport capacity (in terms of people per hour): build more capacity or use existing infrastructure more efficiently. If a five-minute frequency bus service runs on existing roads, people-per-hour capacity of those roads increases by about 60%. That fixes congestion too – for all road users. If those buses run on a separate busway, capacity increases by only another 3%.[1]  It is the service frequency and patronage that determines the increase in capacity, not the infrastructure.

GCP has consistently ignored this fact. Before the Bus Services Act in 2017 it could argue it had very little control over bus services, and therefore needed to woo bus operators with segregated infrastructure on which they could run highly profitable Park & Ride services (even though this strategy undermines less profitable rural bus services). Now, however, the Combined Authority has the power to commission bus services.

GCP has already indicated [2] that it wants to use some of its money to ‘pump-prime’ new, extended and expanded services (just as it is already spending £1.1million per year to subsidise parking at Park & Rides). It can also build travel hubs and other infrastructure to give people more convenient and safer access to bus services, and to give buses significant localised priority.

The electorate voted for change. Will councillors deliver?

[1] Approximate calculation: Typical road capacity of 800 cars/hour = 960 people/hour at an average peak-time occupancy of 1.2 people/vehicle. Each bus, carrying an average of 50 people, replaces two cars, carrying an average of 2.4 people. So, 12 buses/hour increases road capacity by 12 x (50 – 2.4) = 571.2 people/hour or 59.5%. Move the buses onto a separate road, capacity is increased by 12 x 50 = 600 people/hour or 62.5%.

[2] Public Transport Improvements and City Access Strategy presented to the Executive Board on 18 March 2021.


New on the website

Our response to the East-West Rail consultation can be found here.

This article was first published in the Cambridge Independent on 9 June 2021.

Edward Leigh

Edward Leigh is the leader of Smarter Cambridge Transport, chair and independent co-opted member of the Cambridgeshire Police and Crime Panel, chair of the South Petersfield Residents Association, business owner, consultant, and occasional blogger about making the world and Cambridge a better place to live.


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  • You have an embedded assumption here that travellers will choose to occupy a crowded bus, progressing slowly in traffic, rather than a car on the same road. Logically, choosing the bus reduces congestion but people do not think like that. Running buses with few passengers does not improve capacity very much. To make this work the buses must get priority on the roads so there is a clear advantage.

    • The “significant localised priority” mentioned at the very end of the article includes a range of measures, including inbound bus lanes, bus gates (like in Cambridge city centre, Station Rd, Worts’ Causeway and elsewhere), and bus-only cut-throughs (e.g. Houghton Rd on the east side of Huntingdon). This significantly reduces journey times and variability, and makes the advantage of buses very visible to car drivers (more so than a busway over the horizon).