Friday, 27 January 2017

Sustainable travel for Cambridge - we have the technology, not so sure about the will

Cambridge has a massive problem with traffic congestion and it is going to get worse as more houses are built - another 20,000 more homes in the area are planned [1]. Persuading more people to use public transport instead of cars would relieve congestion and lower carbon emissions too. Currently our public transport is unreliable, slow and expensive but it does not have to be like this. Other cities have much better public transport than we do - with sensible routing, integrated electronic ticketing, real time updates, wide and/or multiple doors for fast boarding, real time updates on schedules. Above all we need to make sure buses have priority on the road so they can sail past the fuming car drivers! The new devolved administration for Cambridgeshire and Peterborough will have the powers to make this happen - but we have to ensure they are used.

Bicycles, buses and taxis on a busy street in Cambridge

The Greater Cambridge City Deal is the council's proposal - others include Smarter Transport and Cambridge Connect.
I've been thinking a lot about transport recently because Transition Cambridge Energy Group had a meeting on the topic last week. There are a range of proposals in the Greater Cambridge City Deal from bus lanes to congestion control points generating public outcry. At our meeting Edward Leigh from Smarter Transport and Colin Harris from Cambridge Connect joined us and their contributions were enormously helpful. I strongly recommend you take a look at their proposals. The Smarter Transport suggestions for buses are here and the Cambridge Connect proposals for mass transit are here.

Small increases in capacity won't fix the problem
Cambridge has a big problem with traffic congestion - especially at peak times or if there is an accident somewhere. Commuters adjust to this by travelling early or late to avoid the congestion. This means that simply increasing traffic throughput (e.g. by smarter traffic lights) won't fix the problem. It could make the congested periods shorter, but it won't reduce the actual peak. In fact there isn't nearly as much difference between peak flows and daytime flows as you might expect - as you can see from this chart.
Traffic flow at 4 automatic traffic counter sites in Cambridge [1]l

Buses can carry more people in the same road space
Getting people onto buses increases throughput simply because you can get more people into the same road space. A typical urban trunk road like Huntingdon Road can carry 1000 - 2000 vehicles an hour [2]. One bus every 2 minutes could transport up to 2700 people in the same time.

Even at current low usage rates, buses generate 40% less carbon emissions.
Most buses are not very full most of the time - outside London they carry on average only about 10 passengers at a time. However, even at this low level of usage the carbon emissions are 40% lower than cars [3]. More people on the buses would reduce carbon emissions (as would more efficient buses or electric buses). If more people used the buses the costs ought to go down too, as the fixed costs are spread over more passengers.

People might use the buses more if they were quicker than a car.
However, buses are a poor substitute to car travel for most people. For example they are infrequent, unreliable and slow. Half the problem is that most of the time buses travel in the same stream as the cars and they stop frequently. So they are guaranteed to be slower, no matter what the traffic conditions. The most effective way to persuade people to use public transport is to make sure it is quicker. So how to make sure that buses (or other public transport) are quicker? Here are some ways:
  • Give them separate bus lanes
  • Give them priority at traffic lights - with smart controls like SCOOT as deployed in London
  • Have them stop less often: Smarter Transport recommends introducing express buses stopping only at travel hubs, that are within easy walking distance of most homes and destinations.
  • Make getting on and off quicker by having wide doors and electronic ticket readers so that the driver is not a bottle neck. In London you use an Oyster card, a debit card or a mobile phone app.
We also need real time information and navigation aids.
Public transport also need to be easier to use. This means things like:
  • Making sure that time tabling and routing information is freely available to third party providers of mobile apps. This needs to cover all public transport including trains and trams where appropriate. In fact we mostly have all this already, with apps like Traveline.
  • Making sure that real time bus information is available ditto. Did you know the MyBusTrip app allows you to track Cambridgeshire buses on a map? I am told this information is not available to third party service providers.
  • Having on board signage that updates to show passengers where you are - we have it on trains and trams so why not buses? This is very reassuring for people who are not familiar with the route - when car drives would use an in-car navigation system.
A patchwork of bus lanes on bits of the routes will be ineffective
Making dedicated bus lanes is difficult and expensive if the roads are not already wide enough. But leaving out the difficult bits loses most of the benefit, especially if buses have to merge with existing traffic when the bus lane runs out. The Greater Cambridge City Deal plans involve a lot of bus lanes but objections from local residents look likely to nibble away at these so we will end up with a patchwork at best.

The light rail system proposed by Cambridge Connect is another option. This could be like the one in Nottingham except within the city there is no space for new track so it would run underground. Apparently the geology under Cambridge is very suited to tunnelling. Cambridge Connect have preliminary costings that are eye watering but not out of the question with long term financing. A light rail system has even better carrying capacity than a bus because you can run lots of carriages.

Benefits include greater speed, reduced air pollution and economic growth
All these measures are doable but they cost money - the council needs to do most of the infrastructure (including smart ticketing options) and the bus operators need to do do all the bus stuff - such as sensible routing, real time information, on board signage and smart ticket readers. The light rail system could use mostly private financing. The benefits include:
  • Faster travel for new and existing bus passengers
  • Reduced ticket prices for bus passengers (because once the cost of new infrastructure is paid for the extra running costs will be more than covered by the increase in number of passengers)
  • Less air pollution for everyone in the city and near busy roads
  • Less carbon emissions, contributing to our greenhouse gas target
  • Enables business in the city and around to grow, because the extra staff can actually get to and from work and customers can get to and from shops
Bus lanes can carry more people than car lanes
However, despite all these benefits it is very likely that these these measures will be unpopular with car drivers. Bus lanes are a particular point of fury. Being stuck in traffic next to an apparently empty bus lane is frustrating to say the least. It might seem as though you could double the road capacity by opening the bus lane to normal traffic, but in fact if there are enough people using the buses the single bus lane can carry more than the road space ever could. Some of the other measures benefit car drivers too by reducing the time that buses block the traffic at bus stops.

What will these changes mean for me? Many people are deeply suspicious.
I am sure I have done a good selling job and you are all now convinced - except that (as Edward Leigh pointed out to me) you are all deeply suspicious and want to know how these changes will affect you personally - your commute, your shopping trips, your trips to the cinema and friends or whatever. This is understandable - but very hard to provide until a lot further down the planning process. Besides which, there are lots of related issues I haven't touched on - mostly covered by the extensive Smarter Transport suggestions.

A market driven system will not deliver - we need regulated buses like in London
In any case, none of this can possibly happen as long as transport continues to be market driven. Under current rules, bus companies have no incentive to run routes other than the radial ones that make the most money and no incentive to help their competitors by running an integrated ticketing system.

Most of my examples come from London because they have a regulated public transport system. Legislation in the ongoing Bus Services Bill means that the devolved administration will have considerable powers to control ours too, including the ability to set routes and require service quality standards through franchising [4]. But it still won't happen by magic. We need to make sure our new mayor knows we want it!

What can you do - make sure the new mayor knows you care!
So what can you do? Neither Edward Leigh nor Colin Harris are asking for money at the moment. Rather they want volunteers - especially those with relevant expertise - who can help with preparing and communicating their proposals both to councillors and to the public.

Also, when we get to selecting our mayoral candidates, make sure they know that we care about this by asking lots of questions at hustings.

[1] South Cambridgeshire Local Plan Chapter 3 Strategic Sites (South Cambs. District Council) July 2013
[2] Cambridge Access Study (Mott MacDonald for Cambridgeshire County Council) July 2015
[3] Traffic capacity of urban roads from Design Manual for Roads and Bridges (
[4] Government emission conversion factors for greenhouse gas company reporting
[5] Bus Services Bill FAQS ( Jan 2017


  1. It is probably true that "objections from local residents look likely to nibble away at [City Deal plans for bus lanes] so we will end up with a patchwork at best." However that makes it sound like local residents will be to blame for the poorer bus services we'll have as a result.

    The starting point is that there isn't sufficient space on any radial road to build continuous bus lanes in both directions, even as far as the inner ring road. The 'Do Maximum' option currently being progressed for Histon Rd entails grubbing up almost all the trees and verges, and compulsorily purchasing front gardens to squeeze in a single bus lane only as far as Gilbert Rd. What can be physically accommodated is already so compromised as to be almost worthless, even before local residents (and others who care about how the city looks) start questioning the wisdom of removing all the greenery.

    There are many more significant factors in making bus travel more attractive and reliable, which are explored in Smarter Cambridge Transport's paper on "Can we do better than bus lanes?"

  2. It's remarkable how flat the traffic-counter curve is during the day. 'rush-hour' is only a 10-15% increase. Which I guess just illustrates the same thing as the small half-term difference: 10% is the difference between 'massive congestion' and 'mostly flowing'.

    Given road widths, 'more bus lanes' would be at the cost of having terrible cycling infastructure, or would require cars to be entirely banned from a segment. I think the Smarter Transport plan of restricting vehicle entry rates on the edge of town is the right way to manage road space. Then it doesn't bung up and buses get to queue-jump the major entry radial queues, and not be held up much in-town.

    Here's some very interesting thoughts on the future of travel: Dr Stefan Heck on the 'Impending revolution in travel', about how all of: autonomous vehicles, electric cars, reduced ownership, and mobile comms combine to change many things about how travel is done: