Cardiff Study Assessment
A summary of the following is available on the Cardiff Study page.
The Cardiff case study was made originally for the Department for Transport, but a much more detailed examination and appraisal of the installation of ULTra in Cardiff has been made recently for the European EDICT study (EDICT, 2004). The PRT network studied connects the city centre rail stations (Central and Queens Street), and the shopping area around them, with the rapidly developing Cardiff Bay area about 1.5km to the south. The new waterfront developments contain new offices, shops and leisure facilities, and a substantial amount of new residential development between the waterfront and the central area. The Bay area also contains the Welsh National Assembly building, the new opera house under construction, and the Cardiff County Council offices.
Figure 1: The proposed Cardiff network.
The Network
As proposed, the system is to be developed in three Stages, with an initial pilot loop to demonstrate the practicality and reliability of the concept, then a second phase connecting the Bay Area loop with the city centre and two railway stations as shown in Figure 1: the third phase would extend the network to the north of the central area. The EDICT study examines the second phase, which has 7.7kms of single-track guideway, 80% of it elevated, and 12 stations. 134 vehicles are required to meet the predicted demand for 2006, rising to 176 by 2036.
The demand model used to predict the system’s usage and transfer from existing modes of travel is a conventional logit modal split model, depending on the relative costs of travel in both time and money by the different modes (car, taxi, walk, bus, rail and ULTra). The model parameters which relate to PRT have been estimated from a “Stated Preference” survey of 358 potential users, who were each asked to choose between alternative modes for particular journeys on the basis of realistically estimated travel times and costs.
Although the study is unavoidably hypothetical, confidence in this approach is given by the estimated “Values of Time” implied by the analysis, which were consistent with accepted values obtained from many previous studies (Ove Arup and Partners, 2002). The model was applied to Cardiff City’s estimates of current trip-making between 330 zones into which the whole city area had been divided, based on traffic counts and transport surveys made in 2002 and extrapolated into the future on the basis of predicted demographic changes and expected new development. The latter is obviously very important to this study, where PRT is intended to serve the rapidly-developing Bay Area.
The fare proposed is £1 (€1.50) per vehicle, about 70p per passenger at average occupancies. Focus Group studies under EDICT with people who have ridden on ULTra at the test track suggest that they would be willing to pay two or three times this amount. The demand model predicts that in the base year, 2006, the ULTra system will attract 5.67 million person trips per year, or 4.30 million vehicle trips at an average occupancy of 1.32. Demand is predicted to grow as both commercial and residential development increases in the Bay Area, rising to 5.62 million vehicle trips by 2036, the end of the assessment period.
System Performance
ULTra is very competitive with bus travel, and with walk over longer distances, attracting 61% of present bus users, though only 9% of all walkers since the average walk distance is very short. However, ULTra also benefits bus and rail services by attracting 8% of present car commuters to the Bay Area to use the combination of rail or bus into the centre and then onward by ULTra, an additional 2 million passengers per year. Note that this assumes current availability and cost of car parking: parking may become more constrained in future, increasing the demand for ULTra. Although ULTra’s speed is relatively low, at 40 kph, it is non-stop and provides a much faster journey then do average road speeds in the congested centre. For public transport users, ULTra has the important advantage of involving almost no waiting time, compared with a random mean wait time of 7.5 minutes for the infrequent bus services to the Bay Area, and typically 5 minutes even for more frequent services. Simulation of the ULTra operation suggests that its mean wait time is only 0.3 minutes, because most passengers do not have to wait at all.
Obviously, there are practical and aesthetic problems in running the system through existing built development, but it is potentially much easier to do this with ULTra than with any larger-scale form of tracked public transport. Installing the guideway amongst the new development in the Bay is relatively straightforward, and there are no serious impediments to constructing the infrastructure within the existing town centre along the routes indicated. Indeed, discussion with the planning authorities met a very positive response.
Safety and security have been high priority issues during focus group discussions with the public, and consultations have been undertaken with HM Rail Inspectorate from the early stages of the project, supported by independent safety experts. The Inspectorate have issued a ‘letter of no-objection’ to ULTra’s safety case, and have authorised the carriage of the general public for the trials. The system can also offer significant benefits in personal security since travellers spend little time waiting in potentially insecure places because the immediate availability of a vehicle can be virtually guaranteed at times when few people are around. At all times, trips are only undertaken either individually or with companions chosen by the traveller. All stations will be well lit and under continuous coverage by CCTV, which will also monitor the guideway against intrusion. Direct links to the controller, including CCTV, will be available from all vehicles and from all stations.
In a Focus Group survey of people who had ridden on the trial system, all respondents found the ULTra system ‘Very Easy’ or ‘Easy’ to use, and over three quarters of respondents felt either ‘Very Secure’ or ‘Secure’ using the system. Nobody felt ‘Insecure’ or ‘Very Insecure’. The response to all aspects of the system was very positive, with 70% or more rating each aspect as “excellent” or “good”, and hardly any ratings below “average”. Three-quarters of the passengers thought the elevated sections of track were “not a problem” or “probably OK”, though a quarter were unsure. The ULTra system has been tested by 8 mobility-impaired people and six elderly people in two of the Focus Groups, who considered the system to be easier to use than any other form of public transport, including taxis. An Access Audit has been made of the ULTra vehicle and station in the trial system, and this assessed accessibility for mobility-impaired people to be better than the regulatory requirements for taxis and railways. There were a number of minor criticisms connected with lack of colour discrimination for the partially-sighted, and positioning and size of control buttons in the vehicle and station, but the necessary improvements can be made easily in the final designs. The only concern which is not easily remedied is that, although the DfT “standard” wheelchair has been successfully tested within the vehicle, particularly large types of wheelchair are more difficult to manoeuvre.
Financial and Social Assessment
The total capital cost for the Cardiff system is estimated at £34.3M, with an annual operating cost in 2006 of £2.05M, rising thereafter as demand increases. Revenue is estimated at £4.30M in 2006, rising to £5.62M in 2036. Over the 30-year period of the assessment, the Net Present Value of the revenue less costs is +2.71M at a 3.5% discount rate (a rate considered appropriate to public investment in innovative systems provided measures have been taken to reduce risk), and £8.27M at 6% (the standard public investment discount rate). The demand forecasts are considered to be conservative, and the out-turn performance seems likely to be better than this, especially so since a system which provides such an improved level of service will encourage entirely new trip making. Thus the system easily covers its operating costs, and seems likely to cover its capital costs in full at public project discount rates, but does not provide the higher rates of return demanded for purely commercial operation. It is likely to require some public subsidy for its infrastructure, but at a level which is very small in comparison with conventional tracked public transport. ULTra track is substantially cheaper than conventional LRT track, as is illustrated by a comparison of ULTra with five recent UK LRT systems which showed a mean cost per one-way LRT route-km some 70% higher than for ULTra (EDICT, 2004), yet ULTra has a passenger-carrying capacity as great as LRT at 4800 seats per hour one-way at a 3 second headway.
In addition to the financial returns described above, an assessment of this public scheme needs to include various other social benefits accruing to both users and non-users of the system. These cannot all be monetarised, but they are important because they may contribute to the local policy objectives. The monetarised benefits include:
- The savings in travel time and money accruing to the ULTra users compared with their previous journeys, estimated as the change in the weighted costs of the time components of travel when ULTra is introduced, plus the saving in car operating cost of those car users who transfer. In 2006, this is £3.29M.
- The reduction in congestion, whereby those travellers who continue using the roads benefit from reduced delays as some car users transfer to ULTra. By applying the predicted reduction in total car-kms to the mean speed/flow relationships applicable to Cardiff’s roads it is estimated that 953 passenger-hours will be saved each day (in 2006), or 348,000 per year, with a value of £1.67M per year. In practice the reduction in congestion will encourage some travellers to drive into the city when before they used other modes or went to more local destinations, and this will erode the time savings (though giving benefit to the new travellers), but the extent to which this happens will depend on the City’s policies towards traffic restraint.
- ULTra is a safer mode of transport than either car or foot, and the consequent reduction in accidents can be estimated on the basis of broad average accident rates, and the saving in fatalities, severe and minor injuries costed at standard UK rates. The value of this is £0.52M in 2006.
- The saving in energy, at 9.4 GWhr in 2006, can be costed at the current price of electricity in the UK of £0.08/kWhr to obtain a benefit of £0.92M per year in 2006.
Summary of benefits and costs estimated from 2006 to 2036 for the proposed Cardiff network.
These costs and benefits are summarised in Table 1 on the right
The ULTra vehicle is battery electric and lightweight: its energy consumption per passenger-km is about a fifth that of a car, one third that of rail, and about half that of a heavily laden urban bus. Consequently there are substantial savings in energy use, estimated at the equivalent of 3 million litres of fuel per year in 2006, and parallel savings in emissions. The effects of air pollution on health are serious, and there is evidence to suggest that particulate emissions from traffic may cause more premature deaths than road accidents, but there is no accepted basis for monetarising these benefits. After allowing for the pollutants emitted by the power stations which generate the electricity to recharge the vehicles’ batteries, it is estimated that, over the base year 2006, installation of the ULTra system reduces total emissions by 45 tonnes of carbon monoxide, 3.6 tonnes of volatile organic compounds (VOCs, or hydrocarbons), 5.7 tonnes of nitrogen oxides (NOx) and 0.30 tonnes of particulates or black smoke. The saving in energy also corresponds to a reduction in the greenhouse gas carbon dioxide (CO2) of 3750 tonnes.
Ecological effects are small, since the footprint of the guideway is small, and in the Cardiff application there is no appreciable loss of habitat. The use of de-icing agents in winter may cause some nuisance, however, and will require careful management. ULTra offers noise levels which are likely to be undistinguishable from the background noise, and will cause no vibration problems in the buildings it passes. The guideway has to be segregated, and there are potential problems of community severance here, but in practice much of the track is elevated so that footpaths can pass underneath, and it will pass over all roads it crosses. The design intention is to cause no added severance. There are unavoidable problems of visual intrusion, but these can be minimised by the small scale of the infrastructure and careful design, and will be far less severe than with other forms of tracked public transport. In some aspects the system can add positively to the cityscape, creating an exciting and dynamic addition, especially where it can be integrated directly into new development.
