Evidence on Performance
In this section case studies are presented to demonstrate the empirical evidence of the use of Park and Ride schemes as policy instruments. A summary of an Atkins report containing analysis of several sites in the UK including is presented. A re-evaluation of the Atkins case studies by Parkhurst (2000) is then given. Also included is global information relating to worldwide Park and Ride schemes.
The Travel Effects of Park and Ride Atkins
A report by WS Atkins and the DETR published in September 1998 studied the effects of Park and Ride systems in Brighton, Cambridge Coventry, Norwich, Plymouth, Reading, Shrewsbury and York. Each site was visited and discussions were held with local authorities, car park and bus service operators and city centre managers as appropriate. Questionnaire surveys based upon the behaviour and views of Park and Ride users were carried out in each of the sites, with a second post back questionnaire used in six of the eight sites for non-users of the park and ride. This would help separate the views of these two groups. Overall 1,479 of the questionnaires were returned (25%).
Results found showed that:
The study found that private car mileage did experience a net decrease from the use of Park and Ride facilities and the value of the decrease varied from site to site. The reduction in traffic was more significant in cities that also employed transport strategies that aim to remove long stay car parking in the centre and move it to the Park and Ride site, this effect was noted in York and Cambridge. This policy in York and Cambridge is helping to make it viable to increase the number of park-and-ride sites so decreasing potential diversion distance over time.
Other conclusions were:
Reasons for non-users to avoid Park and Ride were perceived speed, ease of driving directly into the centre, proposed length of stay and limited mobility. Whereas cost, convenience, reliability, frequency, difficulty in parking and faster journey time were the reasons given by users for why they switched to Park and Ride. Of these factors, the non-users and users pointed to cost and journey time being the most likely to influence their decision on whether to switch to Park and Ride or not.
Table 7: Contribution to objectives
Parkhurst 1999 and 2000
A study by Parkhurst (2000) reviewed the work of Atkins for the DETR and offered an alternative appraisal of the same eight park and ride sites by separating the analysis into urban and outer-urban components. Parkhurst considered three types of traffic increase: 1) drivers who are intercepted detouring to reach park and ride sites; 2) passengers switching from existing public transport services; and 3) drivers making additional trips.
Some of Parkhurst's key findings supported whilst others contradicted the Atkins report. These are presented below along with supporting tables.
a) Impact On Urban Areas
The reduction in car vehicle kms is greater than the additional car-equivalent distance run by park and ride bus services in seven of the eight case studies. Bus kilometres are weighted by 2.5 compared to car to reflect the buses’ increased impact per kilometre on congestion, road wear and the environment. In Coventry the additional bus traffic was 2.6 car kms greater per intercepted car, whilst in the remaining seven case studies the reduction in car kms per intercepted car ranged from 1.1 (in Brighton) to 6 in Shrewsbury. Whether this actually results in such a reduction is dependent on the extent to which freed up road space is filled by additional urban traffic.
Table 8: Changes in Traffic in urban area Per Intercepted Car (car kms)
b) Impact On Outer Urban Areas
Results presented in the table below (column 3) suggested an increase in traffic outside of the urban area in all eight case studies as the result of intercepted drivers detouring to reach park and ride sites, passengers switching from existing public transport services and drivers making additional trips. The first impact (detouring) can add between 1.5 car kms (Reading) to 6 car kms onto the outer urban journeys of intercepted car drivers. The second impact (modal switch) adds between 3.4 car kms (Coventry) to 20.5 car kms (Norwich) per intercepted car. The third impact (generated trips) increases car kms per intercepted car by between 4.1 (Shrewsbury) and 25.7 (Norwich).
c) Net Impact on Traffic Growth
The net impact on traffic growth is to increase traffic on the road network overall for each case study by between 0.9 (Shrewsbury) to 20.7 (Norwich) car kms per intercepted car.
Table 9: Changes in Traffic Per Intercepted Car (car kms)
Parkhurst concludes, “Urban-fringe bus-based park and ride provided with dedicated bus services is better described as a policy of car traffic redistribution than a policy of car traffic reduction”.
d) Benefits of Traffic Transfer From Urban to Outer Urban Areas
This will be beneficial where urban congestion and/or environmental externalities in the urban areas are more acute than in the outer urban areas. There might however be greater urbanisation around the park and ride catchment area.
e) Costs and Revenues
After comparing the annualised operating costs & capital costs with revenue from user charges only one scheme (Brighton) was estimated to cover its costs, whilst the others required a subsidy per car intercepted that ranged from £0.11 (York) to £5.87 (Coventry). In terms of subsidy cost per intercepted car km these ranged from £0.02 (York) to £0.53 (Cambridge).
Table 10: Capital and Operating Costs of Park and Ride Sites
Table 11: Cost of Urban Traffic Interception Due to Park and Ride Per Weekday
Table 12: Contribution to Objectives
Text edited at the Institute for