The Invisible Referee

21st Century Traffic Control: The Invisible Referee University of Southampton

Predicting the impact of new railway stations and services

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There is a common perception (even amongst some transport professionals) that the rail network is in a state of decline, but in fact nothing could be further from the truth. UK passenger rail use is currently at record levels and, despite the recent economic downturn, growth in rail travel seems likely to continue. This growth will be accentuated by the need to reduce carbon emissions to meet government targets, which will necessitate considerable mode shift from private to public transport. Expansion in capacity will be required to accommodate these additional rail passengers, and there are a large number of schemes proposed for new railway services, stations and lines. However, only limited funds are available to implement such schemes, and it is therefore important to ensure that this money goes to the projects which will deliver the greatest benefits to passengers in the most cost-effective way. In order to achieve this, a range of work has taken place at the University of Southampton Transportation Research Group to develop modelling and appraisal procedures for assessing the likely performance of schemes to improve rail services.

Where should stations and services go?

Before a new railway station or service can be evaluated, a decision must first be made on its location or route, and we have developed procedures for identifying both potential locations for new stations, and also routes where the current rail service is poor but where capacity exists on the rail network to provide a better service. This allowed 421 possible sites for new stations to be identified on existing rail routes in England and Wales. As well as building new stations, making improvements to existing stations may attract additional passengers, and we have developed models which can forecast the impact of such improvements on usage levels.

How many people will use them?

Once station sites have been identified, it is next necessary to predict how many passengers will use them. Mathematical models have been developed which are capable of predicting the total number of trips per year at a station located at any site in England and Wales. These are based on travel patterns at almost 1,500 existing local stations, and take account of (amongst other things) population, employment, service frequency, car parking provision and proximity to larger stations. The models use a technique called Geographically Weighted Regression (GWR) (developed by a team at the National Centre for Geocomputation at the National University of Ireland), which allows the effect of the factors determining rail passenger numbers to be different in different places. The models suggested that 144 of the station sites identified in England and Wales would be used by more than 100,000 passengers per year if they were constructed.

Where will people go?

In order to estimate how much fare revenue will be generated by new stations or services, and to enable service patterns to be adequately planned, it is necessary to forecast the destinations of these additional passengers. A further set of demand models have therefore been developed which can predict where passengers using new stations or services are likely to travel to and from. These were based on data on rail travel from existing stations, and the results from the models can be used to map the travel patterns which would be expected if the schemes were implemented.

What are the benefits and costs?

To assess whether or not a new station or service should go ahead, it is necessary to calculate the total benefits and costs of the scheme. Fare revenue can be estimated based on the predicted trip patterns, and additional revenue may also be generated from station car park charges and from renting station buildings and retail units to private businesses. Indirect financial benefits are also likely to be generated, as additional passengers will obviously derive some level of benefit from their travel as otherwise they would not choose to use the train, and it is possible to estimate these benefits in financial terms. Many of the additional rail trips will previously have been made by car, and the consequent reductions in congestion, noise and pollution can also be given a financial value. Our research has also shown that the construction of new stations can lead to a 7-10% increase in house prices in the surrounding area, generating benefits for local residents.

New stations and services will obviously incur additional costs. Station construction can be extremely expensive, and once the station is open there will be ongoing maintenance and operating costs. Trains making additional stops at new stations will inevitably consume more fuel because of the extra power used up in acceleration, and this will incur a cost. These additional halts also cause a small disbenefit for existing passengers on trains serving the new station by extending their journey times. The provision of new rail services can also be surprisingly expensive, due to the need for additional trains and staff, and in general predicted usage levels will need to be much higher to justify the operation of a new service than to justify the construction of a new station on an existing route.

Is there a case for construction?

In order to decide whether or not a scheme should get the go ahead, the various costs and benefits must be brought together in a cost-benefit analysis to assess its value for money. We have produced a spreadsheet which can automatically carry out such an analysis once all the required data have been input. This allows different schemes to be compared and those which have the best case for implementation to be identified.

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