No, Cambridge should not be trying to innovate in public transport. Sometimes, boring is better

One of the prettier Cambridge colleges. Image: Getty.

Cambridge likes to style itself as a place where ideas are formed. “Cambridge ideas change the world,” according to the university.

And the city is currently having a lot of ideas about how to solve its traffic problems. The region’s metro mayor, James Palmer, is on record as supporting the idea of an underground rapid transit system for the city. Local campaign groups, business lobbyists and professors alike have weighed in with their ideas, and sketched out exciting maps of future transport systems.

But while the city supports copious innovation in electronics and biotech, it absolutely should not be trying to innovate in public transport.

Here’s why: Cambridge is really small for a city. The 2011 census put its population at 123,000, but the city is growing, so it’s perhaps 130,000 now. The current record holder for “smallest city with a metro system” is Lausanne, Switzerland – population: 146,000, but in an urban area of 400,000 – which has a light rail line and an underground metro line. The latter is less than four miles long, and cost around half a billion pounds to build when it opened in 2008. It’s also on a really steep hill: the metro allows people to easily travel between the upper and lower parts of the city. This is definitely not a problem that Cambridge has.

So, what could we do for Cambridge? Lots of people argue for trams. They’re fast, quiet, give a smoother ride than a bus, and the fixed infrastructure means that they raise property prices along their route, which can help with financing them.

For such a system to work properly, however, you’ve got to give it a dedicated route – or the trams will get just as stuck in traffic as the buses already are. That means closing a lot of roads in the city to cars, in order to make space for public transport.

Given we can’t find enough street space to give priority for buses on the roads into the city, it’ll be just as difficult for trams. Even worse: tram tracks are really not kind to cyclists. In a city where 29 per cent of the population cycles to or from work, disrupting cycling is going to be really counterproductive.

The “Isaac Newton Line” – a massive proposed light rail system with four underground stations in the city, with options to be extended all over the region (click to expand). If only money grew on trees. Image: CambridgeConnect.

“But wait,” say various armchair engineers, “we could have a tunnel!”

That’s true. We could have tunnels for trams in the city centre, and run them on the surface further out.

Now you’ve got a tram system with underground stations, so that’s more expensive to build, and also more expensive to operate (because underground stations are likely to need to be staffed for safety).  You’ve also got to work out where to put the portals.

Another Cambridge – the one in Massachusetts – has a tunnel for its trolleybuses, to allow passengers to interchange easily with the underground metro at Harvard Square. The ramps to the tunnel – which is only just below the road surface – are 100m long. If you wanted a tunnel under Cambridge, UK, you’d end up doing some serious demolition to make enough space.


The Harvard bus tunnel in Cambridge, MA: the northern approach ramp runs through a park, and the southern one is underneath the One Brattle Square shopping complex. Both require a strip about 100m long. Image: Open Street Map.

“Can’t we have a more innovative solution?” Well, step forward the Affordable Very Rapid Transit, or AVRT. This is the brainchild of John Miles, a professor of civil engineering.

He proposes a wheel-shaped network of tunnels, with a single central underground station, and connections to a series of sites around the periphery.

AVRT: here’s a sexy computer rendering of a non-existent eight-wheeled autonomous bus. Image: Connecting Cambridgeshire.

To save money, the tunnels will be single-track, with driverless vehicles shuttling back and forth between stations at each end. Passengers will be required to change at every station – because this will save on the cost of the signalling.

A map of the AVRT proposal: click to expand. Each of the blue lines is a tunnel served by vehicles shuttling back and forth, with no through connections. That central underground station is going to be an overcrowding nightmare as everyone tries to change between four different routes all at once. Image: Smart Cambridge.

Miles’ reports (vol. 1  and vol. 2 ) read a lot like he’s trying to reinvent the wheel from first principles. Many aspects of his design resemble the now-30-year-old Lille Metro, which isn’t even referenced.

There’s a very good reason why Cambridge should not spend any further public money on such schemes. There’s one thing guaranteed to be more risky and expensive than a new rapid transit system – and that’s a new rapid transit system based on entirely novel and untested technology.

Cambridge is simply too small to take the risk. It’s already been burned by the Cambridgeshire Guided Busway, another grand experiment that ended up taking longer, costing more,  and looking like it’s going to be more expensive to maintain than previously thought.

So what should the city do? For a fraction of the cost of rapid transit, Cambridge could:

  • Build more segregated cycle lanes and cycle routes;
  • Use the mayor’s powers to take control of the local bus franchise, and give it sensible unified ticketing;
  • Extend frequent bus routes out to the surrounding villages, and reduce their dependence on park and ride and city centre parking;
  • Fund electric or hybrid buses to reduce noise and air pollution in the city;
  • Fund improvements to the rural heavy rail lines, giving a higher frequency service to nearby towns like Newmarket.

It’s not as exciting – but it’s much lower risk and much higher reward. Cambridge may be the best place to innovate for many industries, but public transport definitely should not be one of them.

Mike Prior-Jones is a Cambridge-based engineer.

Why not read these related articles? Are trams really better than buses? What is bus rapid transit – and why doesn’t every city want one


“Stop worrying about hairdressers”: The UK government has misdiagnosed its productivity problem

We’re going as fast as we can, here. Image: Getty.

Gonna level with you here, I have mixed feelings about this one. On the one hand, I’m a huge fan of schadenfreude, so learning that it the government has messed up in a previously unsuspected way gives me this sort of warm glow inside. On the other hand, the way it’s been screwing up is probably making the country poorer, and exacerbating the north south divide. So, mixed reviews really.

Here’s the story. This week the Centre for Cities (CfC) published a major report on Britain’s productivity problem. For the last 200 years, ever since the industrial revolution, this country has got steadily richer. Since the financial crash, though, that seems to have stopped.

The standard narrative on this has it that the problem lies in the ‘long tail’ of unproductive businesses – that is, those that produce less value per hour. Get those guys humming, the thinking goes, and the productivity problem is sorted.

But the CfC’s new report says that this is exactly wrong. The wrong tail: Why Britain’s ‘long tail’ is not the cause of its productivity problems (excellent pun, there) delves into the data on productivity in different types of businesses and different cities, to demonstrate two big points.

The first is that the long tail is the wrong place to look for productivity gains. Many low productivity businesses are low productivity for a reason:

The ability of manufacturing to automate certain processes, or the development of ever more sophisticated computer software in information and communications have greatly increased the output that a worker produces in these industries. But while a fitness instructor may use a smartphone today in place of a ghetto blaster in 1990, he or she can still only instruct one class at a time. And a waiter or waitress can only serve so many tables. Of course, improvements such as the introduction of handheld electronic devices allow orders to be sent to the kitchen more efficiently, will bring benefits, but this improvements won’t radically increase the output of the waiter.

I’d add to that: there is only so fast that people want to eat. There’s a physical limit on the number of diners any restaurant can actually feed.

At any rate, the result of this is that it’s stupid to expect local service businesses to make step changes in productivity. If we actually want to improve productivity we should focus on those which are exporting services to a bigger market.  There are fewer of these, but the potential gains are much bigger. Here’s a chart:

The y-axis reflects number of businesses at different productivities, shown on the x-axis. So bigger numbers on the left are bad; bigger numbers on the right are good. 

The question of which exporting businesses are struggling to expand productivity is what leads to the report’s second insight:

Specifically it is the underperformance of exporting businesses in cities outside of the Greater South East that causes not only divergences across the country in wages and standards of living, but also hampers national productivity. These cities in particular should be of greatest concern to policy makers attempting to improve UK productivity overall.

In other words, it turned out, again, to the north-south divide that did it. I’m shocked. Are you shocked? This is my shocked face.

The best way to demonstrate this shocking insight is with some more graphs. This first one shows the distribution of productivity in local services business in four different types of place: cities in the south east (GSE) in light green, cities in the rest of the country (RoGB) in dark green, non-urban areas in the south east in purple, non-urban areas everywhere else in turquoise.

The four lines are fairly consistent. The light green, representing south eastern cities has a lower peak on the left, meaning slightly fewer low productivity businesses, but is slightly higher on the right, meaning slightly more high productivity businesses. In other words, local services businesses in the south eastern cities are more productive than those elsewhere – but the gap is pretty narrow. 

Now check out the same graph for exporting businesses:

The differences are much more pronounced. Areas outside those south eastern cities have many more lower productivity businesses (the peaks on the left) and significantly fewer high productivity ones (the lower numbers on the right).

In fact, outside the south east, cities are actually less productive than non-urban areas. This is really not what you’d expect to see, and no a good sign for the health of the economy:

The report also uses a few specific examples to illustrate this point. Compare Reading, one of Britain’s richest medium sized cities, with Hull, one of its poorest:

Or, looking to bigger cities, here’s Bristol and Sheffield:

In both cases, the poorer northern cities are clearly lacking in high-value exporting businesses. This is a problem because these don’t just provide well-paying jobs now: they’re also the ones that have the potential to make productivity gains that can lead to even better jobs. The report concludes:

This is a major cause for concern for the national economy – the underperformance of these cities goes a long way to explain both why the rest of Britain lags behind the Greater South East and why it performs poorly on a

European level. To illustrate the impact, if all cities were as productive as those in the Greater South East, the British economy would be 15 per cent more productive and £225bn larger. This is equivalent to Britain being home to four extra city economies the size of Birmingham.

In other words, the lesson here is: stop worrying about the productivity of hairdressers. Start worrying about the productivity of Hull.

You can read the Centre for Cities’ full report here.

Jonn Elledge is the editor of CityMetric. He is on Twitter as @jonnelledge and on Facebook as JonnElledgeWrites

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