A lesson from Plymouth

In the excellent Urban Transport Without The Hot Air by Steve Melia, there’s a study that has important implications for Cambridge and Cambourne.

Ivybridge is a small town in Devon, just under 10 miles from Plymouth, connected by a dual carriageway and a railway line. The journey time by car to central Plymouth in the morning peak is 20–35 minutes; by bus it’s 31 minutes; by train it’s 14 minutes. Yet 95% commute by car. The train service could be more frequent, but there just isn’t the demand to warrant more services.

Cambourne is a similar size and distance from Cambridge. 85% commute by car. Would building a busway or a light rail line to Cambourne make a big difference?

The Local Plan strategy is for the population of the ‘Cambourne corridor’ to grow by 75% over the next 15 years. If the proportion that commute to Cambridge remains the same, that’s an extra 2,000 trips per day. Acknowledging that the A1303/Madingley Rd cannot take any more traffic, then 2,300 of 4,700 commuter trips in the future must be made by alternatives to driving, i.e. almost 50%. Is that remotely plausible?

The problem is that commuting accounts for only about one in six journeys. If you live in Cambourne, most of your shopping, leisure and other trips require a car. Planned investment in the A428 and A421 will make it even easier to drive to St Neots, Bedford and Milton Keynes, so more people will. Once you have a car and a dual carriageway on your doorstep, public transport will never be your first choice.

We can and should improve the quality and convenience of the bus service from Cambourne, and build a Park & Ride at the Girton Interchange. This would reduce congestion and accommodate some growth in commuting along the A428.

But, as campaigners against the Bourn Airfield development have been saying all along: large- scale development will lead inevitably to a large growth in car traffic. Villages around Cambridge will suffer most, as more and more cars pour through them to reach the M11, A14 and Cambridge Park & Rides.

Is the Local Plan strategy right for South Cambridgeshire?

This article was first published in the Cambridge Independent on 26 April 2017.