Posted by: wesleyjohnston | September 5, 2012

Belfast’s Big Gamble – STEM bus measures

Belfast is currently in the middle of a project to re-allocate road space in Belfast City Centre from general traffic to buses (and bicycles, taxis and motorbikes). The project is called Streets Ahead Enabling Measures, or STEM for short. It has got public attention over the past week because the opening of the new Oxford Street bus lane coincided with the schools going back. So far, feedback has been a mixture of positive and negative with car drivers reporting either no change or longer journey times, and bus users reporting either no change, or shorter journey times.

STEM: The Theory

As European cities go, Belfast is a relatively car-dependent city. This means that quite a lot of people move about the city by car. This in itself is fine, as cars are convenient, comfortable and allow travel to almost anywhere.

However, problems arise whenever the demand from car drivers exceeds the availability of road space. The result is congestion, when long tailbacks form and journey times go up. In Belfast city centre, this situation occurs twice a day – during the morning rush hour, and during the evening rush hour. During the working day, congestion is limited to certain very popular routes, eg Great Victoria Street or the Lisburn Road. There is no significant congestion in the evenings.

Since most people agree that we want Belfast City Centre to be a lively and prosperous place, we want the City Centre to be accessible to as many people as possible. With the capacity of the city centre road network fixed, the only way to increase the capacity of the road network is to switch people to a method of travelling that is a more efficient use of road space – which in Belfast means buses, bicycles or walking. If you succeed in shifting a sufficient number of people onto buses, then you can squeeze more capacity out of the existing road network, and make the city centre more prosperous. Plus you get to feel good about lowering carbon emissions.

However, without bus lanes such a switch is never going to happen. Why would someone, if given the choice, choose to sit on a bus rather than a car if they’re both going to be in the same traffic jam? The only way this would have any chance of working is if the bus offers an actual advantage over the car, partly in terms of price, but mainly in terms of journey times.

So the theory goes something like this:

  1. 1000 people commute by car along a road with 4 lanes. The road is at capacity, so no more cars can fit on it. But we want to allow more than 1000 people to use it.
  2. We convert 1 lane to a bus lane. Now only 750 people can commute by car, so initially there is a big tailback as congestion worsens.
  3. However, people can now see the buses whizzing past on the shiny new bus lane, so 250 of them start to use the bus. The congestion returns to its previous level, and the same 1000 people are once again successfully commuting.
  4. However, the buses have plenty more capacity than this, so a further 250 people decide to go into the city centre by bus. These are people who previously didn’t bother.
  5. So now the road is carrying 750 car drivers and 500 bus passengers. Hey presto, we’ve increased the capacity of the road to 1250 people!

So, provided the number of people who start using the bus (or bicycle or walks) exceeds the number of people displaced by the increased congestion, then the scheme works. This is a critical point, and I will come back to it.

STEM: The Price

In Belfast the car capacity of various roads are being reduced by different amounts. Oxford Street sees a reduction of 25%, from the original 4 lanes to 3 lanes. Other roads are seeing a much more severe loss of capacity. For example, Wellington Place and Chichester Street, which are the main west-to-east route across the city centre, are seeing a loss of capacity of 67%, from 3 lanes to 1 lane. This has yet to happen, and I would expect to hear a lot about this when it goes live.

The map below shows the loss of capacity for general traffic that various roads will see.

  • Green = no loss of capacity
  • Yellow = up to 40% loss of capacity
  • Orange = 40% to 60% loss of capacity
  • Red = 60% – 75% loss of capacity


STEM: The Gamble

Recall the lines of reasoning that I outlined above? Well, there are at least three crucial gambles in this line of reasoning as it applies to Belfast.

Firstly, there is the gamble that if congestion increases and/or bus journey times improve, people will switch to the bus. This assumes that the two forms of transport are interchangeable. However, there are many reasons why a person might choose a car over a bus. Some people need their car for work. Others are carrying too much luggage for a bus. Others have multiple messages to do en route. Others simply don’t like buses. All these people will try to continue to use a car, regardless of the loss of road capacity.

Some people don’t need a car and will easily make the transition to the bus. The point is that we don’t know how many are in the former category, and how many are in the latter. If the people of Belfast fall largely into the first category, then the gamble will fail and the buses will not be able to make up for the loss of capacity for general traffic. If, on the other hand, the people of Belfast fall largely into the second category, then the gamble will work, and the buses will be able to absorb the difference, and the city will benefit.

Secondly, there is the gamble that the city centre will remain attractive to shoppers and employers after these changes have been made. Belfast City Centre exists as a strong retail core because, being completely surrounded by a huge doughnut of residential areas, it is one the most accessible parts of the city. It does not exist by right, and there is no law saying that it will continue to play this role. There are plenty of alternatives for shoppers in the form of out-of-town shopping centres and nearby alternatives such as Lisburn. There are plenty of alternatives for employers in the form of business parks and industrial estate.

For people who are going into Belfast City Centre to shop, some may decide that if it’s harder to take their car into town, then they’ll just go to Forestside or the Abbey Centre instead. Switching to the bus is not the only alternative – they may not visit the city centre at all. On the other hand, some people who are driving into town to shop may well decide to switch to the bus.

Similarly, employers who currently have offices in the city centre may find it harder to recruit expert staff if the staff are finding it more difficult to get to the city centre, especially if some of those employees need cars for work, eg salespeople. Some businesses may choose to relocate to a more convenient place for cars such as an out of town industrial estate. But perhaps most employees may be fine about the switch to buses and all will be well. However, it’s possible that many will not be fine.

As before, the point is that we don’t know how many are in the former category, and how many are in the latter. This second gamble will stand or fall on how the people of Belfast view the accessibility of the city centre compared to other alternatives. And we don’t know.

Thirdly, there is the oft-quoted fact that 60% of vehicles driving east-west through Belfast city centre have no destination there, and are simply travelling through. This traffic is therefore strategic traffic, whose destination may even lie outside the city centre entirely, eg a doctor from east Belfast going to a surgery in Lisburn, or a lorry going from the Newtownards Road to the Falls Road. To the south of the city centre, the route past City Hall is the obvious choice. It’s not at all a satisfactory situation to have strategic traffic passing through the heart of the city centre, but that’s the way things are right now.

This does not happen to the north of the city centre because the City Centre Ring (Millfield, Dunbar Link etc) takes most of this traffic. However, the southern section of the ring road was never built (you can see the land reserved for it).

The STEM project will see the capacity of this route drastically cut, in some cases by two-thirds. The third gamble is that all the strategic traffic displaced by this cut in road capacity will be able to find an alternative route. The obvious candidates are further north (City Centre Ring or M3/Westlink) or further south (Donegall Pass or Ormeau Avenue).

Remember that the 60% of people who do not have a destination in the city centre, may find it much harder than those commuting into the city centre to find a public transport alternative. If enough people find alternatives, then there will be no extra congestion and the gamble will pay off. If, however, a significant number decide to stay in their cars, then these other roads will see increased congestion and the side effect will be to snarl up the strategic road network and perhaps even damage the regional economy.

As before, we just don’t know.

STEM: The Verdict?

For the mathematicians among you, the success of STEM hinges on a single variable. Let us call it x, where x is the number of people who choose to switch to alternative forms of transport as a result of STEM. There are two possible outcomes:

Firstly, x may be greater than the loss of capacity for cars in the city centre. In this case, the gamble pays off and STEM will have been a success. Jobs and retail will gravitate to the city centre, carbon emissions will fall and the social scene will thrive.

Alternatively, x may be less than the loss of capacity for cars in the city centre. In this case, the gamble fails, and STEM will have been a disaster. Retail and jobs will move further to the periphery of the city, carbon emissions will be unchanged and the social scene will decline.

Please realise – we do not know the value of x. It hinges entirely on the actual choices that will be made by the real people of Belfast in the next few years.

There are plenty of examples of cities in the world which have tried something similar, and it has been a success. x has been greater than the loss of capacity for cars. However, there also example of places in the world which have tried to restrain cars and it has not been a success. x has been less than the loss of capacity for cars. Belfast is its own city with its own very particular history. We cannot assume it is like any other place.

The only way to find out is to actually try it.

This is why I support the STEM measures. If we maintain the status quo, then we will never know. However, by implementing STEM we can test the hypothesis. It is my sincere hope that the value of x will exceed the loss of capacity for cars, in which case STEM will have been a success. However, we need to be prepared for the possibility that it does not work. In this case, we need to be courageous enough to admit this and restore the previous balance of road space.



  1. Nice piece. We must live quite near each other? From Ballyhackamore into town I use Comber Greenway and Albertbridge Road and it takes just 20 minutes. It ranges from delightful (greenway) to ok on the way in other than the section over the Lagan and the lane change at the markets (where the road is 7 lanes wide.) The way home is frankly terrifying for much of it and I’m expereicned urban cyclist – no bus lanes and cycle lanes have always a car or 5 parked in them! Big sigh of releif when I reach Greenway for a few minutes of bliss. If we are going to fulfill the potential that cycling can make to transport in Belfast we need to design roads to make cyclists feel safe, as well as coming up with as much traffic free network as possible. STEM will be a help for experienced cyclists but for the less confident lets start with a bridge from Gasworks to Ormeau Park as shown in Belfast Metropolitan Transport Plan.

  2. A crazy thought out scheme that will inflict huge damage to an already battered retail sector in the city. Combined with the cringeworthy forthcoming done on the cheap- ‘rapid transport’ scheme which we be just a bus with fancy wheel covers, the city is witnessing yet another glorious missed opportunity

  3. […] phone-ins to vent their frustration at the significantly longer commutes that many face. Since I am on record as having said that the scheme is a big gamble, but one that is worth trying, it’s time to […]

  4. It is important to remember that this is phase 2 of a 6 phase plan.

    By constraining traffic flow through the City Centre travel times will increase (how they could get worse on the Ormeau Road I don’t know). This will improve the business case for rapid transport and inner-ring south.

    By phasing Belfast On the Move in this manner The Roads Service are effectively creating strong arguments for implementing the rest of the scheme, no doubt in repsonse to half arsed funding commitments from DRD / the executive.

    It is a gamble no doubt. But I think they might just pull a blinder and I am completely behind them.

    For the record I think people who live within 2 miles of the City Centre should be charged to travel into the City Centre. Unless these residents have real health reasons for not getting the bus, walking or cycling there is absolutely no justification for them to be driving into the City Centre, except lazyness offcourse.

  5. […] the bus lane behind City Hall was introduced I blogged about the prospects for Belfast on the Move, which sees road space reallocated away from general traffic to facilitate buses, cyclists and […]

  6. Hi great blog! Does running a blog similar to this require a
    massive amount work? I’ve virtually no understanding of computer programming however I had been hoping to start my own blog soon. Anyhow, if you have any suggestions or techniques for new blog owners please share. I understand this is off topic nevertheless I simply needed to ask. Thank you!

    • No, it’s relatively simple – I use WordPress as you can see. It’s very easy to use.

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