Congestion control points

This article was published in 2016, in Newsletter 127.

The City Deal is proposing a number of ‘Congestion Control Points’. What is a congestion control point, how do they work, and where are they proposed to be used?

The basic principle behind the City Deal is increasing economic activity through investment in infrastructure. The funding is limited, only £100m. Whilst this sounds like a lot of money, it cannot pay for something truly transformational like an underground metro system. Therefore, most of this money is being used to increase the speed and reliability of buses as well as to increase the attractiveness of cycling. The main guide to success will be the number of people who shift modes. That is traffic engineering speak for more people getting on buses and riding bicycles, and fewer people driving cars.

A congestion control point is therefore aimed at making bus and cycle traffic move efficiently. Given that we have limited road space, and the £100m won’t buy all the houses required to widen every road in the city, the only other way to give priority is to remove the congestion at key locations to enable the prioritisation of bicycle and bus traffic.


The principles used for the congestion control points are the same as those used successfully in the core traffic scheme. Remove through car traffic from an area and the area becomes easier to move round on a bicycle or in a bus.

To achieve this, you have to ‘cut’ roads. If you cut the wrong roads then the traffic chaos will be worse than now. However, if you cut at the right places then the traffic will be significantly better, and more people will be encouraged to change mode. For example, if you cut Queen’s Road somewhere along the Backs, then you probably also need to cut Grange Road, otherwise it would become a rat-run. If you cut both, then traffic moving between the two would have to use either the M11 or Elizabeth Way bridge.


Each congestion control point does not stand on its own, but works in concert with all the other points. The City Deal therefore proposes different configurations that have different costs and benefits.

There are three options currently on the table that will significantly enhance cycling in our city.

Option 1: Inner Ring Road Closures. Grange Road, Queen’s Road, and East Road. This option proposes to cut north/south traffic on the west side of the city, as well as on East Road outside ARU where the road space is most constrained.
Image as described adjacent
Option 5: Bus Route Road Closures. East Road, Hills Road, Mill Road and Coldhams Lane. This option closes the main routes used by buses where those buses experience significant delays and unreliability due to general traffic congestion. Critically, this closes Mill Road and Coldhams Lane over the railway to the north of the central station, making such routes significantly more attractive to cycle along. It also closes Hills Road just south of the Catholic Church junction.
Image as described adjacent
Option 6: Inner Ring Road and Bus Route Road Closures. Grange Road, Queen’s Road, East Road, Hills Road, Mill Road, and Coldhams Lane. Option 6 combines options 1 and option 5 to have the most benefit in reducing congestion within the city, but would also require the biggest change in travel behaviour.
Image as described adjacent


To reduce the street clutter, each congestion control point would be enforced using an Automatic Number Plate Recognition camera. These would recognise the number plates of each vehicle passing through the closures and check whether it is a registered taxi, bus, or emergency vehicle. If not, then a fixed penalty notice would be issued. Typically, such penalties are £60. Cycles would be allowed through for free.

The periods of time when such enforcement would be active are yet to be published, but are likely to cover the times when the existing volume of traffic exceeds the threshold for efficient bus services. This is expected to be the morning rush hour, from say 7am until 10am, and the afternoon peak from 4pm until 6.30pm.

One critical aspect of this scheme is the management of the first few weeks. In some locations, similar schemes have failed because publicity had been poor and people driving cars didn’t realise they had broken the rules until they received a penalty notice a week later. If 200,000 people received tickets, then political pressure would become very strong to abandon the issue. Instead of penalty notices, for the first month, brochures could be sent instead containing information about the scheme and alternatives such as newly enhanced bus routes. Physical barriers on the street, manned by people to strongly recommend people not to pay £60 to pass a given point for the first few weeks, may be required. The same system of ANPR cameras would also replace the rising bollards in the city centre core traffic schemes.

It would also be useful if a smart city could help people plan their trips, perhaps offering alternatives such as cycle routes or bus routes.

The workplace parking levy, a £375 annual charge for each car parking space provided by employers, is predicted to raise somewhere between £7m and £11m that will be used to subsidise more buses, make the Park & Ride sites free to park, make junctions safer and build segregated cycleways along the main roads and out to villages.


To enable more economic activity in the city, we need more people to be able to move through the city quickly and efficiently. This means that we need to move people out of private vehicles and onto buses and cycles. Congestion control points provide a major tool to encourage people to cycle, by freeing up road space, or to use a bus. When combined with the revenue from the workplace parking levy that can be used to subsidise buses and build better infrastructure, it is possible that Cambridge could be transformed into a fantastic place to live, work and play.

Robin Heydon