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

 
 
 
 

What can other cities learn about water shortages from Cape Town’s narrow escape from ‘Day Zero’?

Cape town. Image: Pixabay/creative commons.

Cape Town was set to run dry on 12 April, leaving its 3.7m residents without tap water.

“Day Zero” was narrowly averted through drastic cuts in municipal water consumption and last-minute transfers from the agricultural sector. But the process was painful and inequitable, spurring much controversy.

The city managed to stave off “Day Zero,” but does that mean Cape Town’s water system is resilient?

We think not.

This may well foreshadow trouble beyond Cape Town. Cities across the Northern Hemisphere, including in Canada, are well into another summer season that has already brought record-setting heat, drought and flooding from increased run-off.

Water crises are not just about scarcity

Water scarcity crises are most often a result of mismanagement rather than of absolute declines in physical water supplies.

In Cape Town, lower than average rainfall tipped the scales towards a “crisis,” but the situation was worsened by slow and inadequate governance responses. Setting aside debates around whose responsibility it was to act and when, the bigger issue, in our view, was the persistence of outdated ways of thinking about “uncertainty” in the water system.

As the drought worsened in 2016, the City of Cape Town’s water managers remained confident in the system’s ability to withstand the drought. High-level engineers and managers viewed Cape Town’s water system as uniquely positioned to handle severe drought in part because of the vaunted success of their ongoing Water Demand Management strategies.

They weren’t entirely mistaken — demand management has cut overall daily consumption by 50 per cent since 2016. So what went wrong?


Limits to demand management

First, Cape Town’s approach to water management was not well-equipped to deal with growing uncertainty in rainfall patterns — a key challenge facing cities worldwide. Researchers at the University of Cape Town argued recently that the conventional models long used to forecast supply and demand underestimated the probability of failure in the water system.

Second, Cape Town’s water system neared disaster in part because demand management seemed to have reached its limits. Starting late last year, the city imposed a limit on water consumption of 87 litres per person per day. That ceiling thereafter shrunk to 50 litres per person per day.

Despite these efforts, Cape Town consistently failed to cut demand below the 500m-litre-per-day citywide target needed to ensure that the system would function into the next rainy season.

The mayor accused the city’s residents of wasting water, but her reprimanding rhetoric should not be seen as a sign that the citizens were non-compliant. The continuously shrinking water targets were an untenable long-term management strategy.

Buffers are key to water resilience

In the end, “Day Zero” was avoided primarily by relying on unexpected buffers, including temporary agricultural transfers and the private installation of small-scale, residential grey-water systems and boreholes in the city’s wealthier neighbourhoods. The former increased water supply and the latter lowered demand from the municipal system. These buffers are unlikely to be available next year, however, as the water allocations for the agricultural sector will not be renewed and there is uncertainty in the long-term sustainability of groundwater withdrawals.

For more than a decade, Cape Town has levelled demand, reduced leaks and implemented pressure management and water restrictions. This made Cape Town’s water system highly efficient and therefore less resilient because there were fewer reserves to draw from in times of unusual scarcity.

The UN Water 2015 report found that most cities are not very resilient to water risks. As water managers continue to wait for climate change models to become more certain or more specific, they defer action, paralysing decision-makers.

If we really want our cities to be water-resilient, we must collectively change long-held ideas about water supply and demand. This will require technological and institutional innovation, as well as behavioural change, to create new and more flexible buffers — for example, through water recycling, green infrastructure and other novel measures.

Although Cape Town avoided disaster this year, that does not make it water-resilient. Despite the arrival of the rainy season, Cape Town is still likely to face Day Zero at some point in the future.

The ConversationThere’s a good chance that the city is not alone.

Lucy Rodina, PhD Candidate, University of British Columbia and Kieran M. FindlaterUniversity of British Columbia.

This article was originally published on The Conversation. Read the original article.