20/01/2019
Over the past year the Combined Authority has been preparing the Strategic Outline Business Case for the “CAM Metro”. The work is being carried out by consultants Steer (formerly ‘Steer Davies Gleave’), with due diligence being provided by Arup. The report is intended to appear in the first quarter of 2019. A broad conceptual outline of the “CAM Metro” was published by the Combined Authority in January 2018 in the report Steer prepared on options for mass transit for Cambridge. In summary, CAM is an acronym for “Cambridgeshire Autonomous Metro”, and broadly adopts the metro network proposed by Cambridge Connect, including tunnels. Artist’s impressions show the CAM vehicle has a similar appearance to a modern light rail vehicle although it has rubber tyres and would run on road surfaces, while a light rail vehicle has steel wheels that run on rails.
During 2018 Cambridge Connect examined evidence for the alternative modes, and compared rubber-tyred bus solutions against steel-wheeled light rail. There are a range of advantages of steel wheels on rail, including energy efficiency, almost zero pollution, physical guidance, the ability to drive modal shift, and the low risks of a proven technology. Some benefits suggested for the bus-based solution include potentially lower costs of implementation and potential to operate on existing roads which may offer greater flexibility.
Rubber-tyred vehicles – even if electric –
- produce harmful emissions of fine particulates from tyre and road wear in quantities similar to the pollution from conventional vehicle tailpipe emissions.
- are substantially less energy-efficient, so a rubber-tyred metro will consume a great deal more electricity than a rail metro. This is a concern for Cambridge, where the electricity grid is under increasing pressure, and is also a concern in view of future electricity supplies and climate change. Over the millions of miles that will be run on a metro, this difference will be substantial.
- produce thousands of waste tyres per year, which will require disposal / recycling. Modern tyres are composed principally of synthetic petro-chemicals, with relatively little rubber content, and this is both harmful for the environment and in relation to climate. Synthetic plastic particles from tyre wear are discharged into the environment, water courses and eventually the oceans.
Cambridge Connect is continuing to examine the strengths and weaknesses of both options, although presently considers the evidence most strongly supports light rail as the best solution for a Cambridge metro. We acknowledge light rail may incur some additional up-front investment costs in laying rails, although the advantages outweigh this when considered over the long-term.
In particular, it is essential that the adopted metro system maximises potential modal shift, for unless the new system can draw substantially more people out of cars and onto public transport then it will fail to address the fundamental problems in the regional transport network. Most evidence shows that light rail is much more successful at attracting people onto public transport than buses, and this should be an extremely important consideration when considering options for a Cambridge metro.
We look forward to publication of the Strategic Outline Business Case for the CAM Metro, which we hope will appear in the next few months.
