【正文】 uire an objective scoring method only available via a transport simulation model. Providing parking of acceptable size, location and type is considered critical to the attractiveness of the town centre retail and mercial environments and hence formed a major part of the modelling exercise.Car park searchingAs the primary goal of all three models was to study theimpact of car parking on urban traffic congestion, the strategies for allocating vehicles to car parks within the model and subsequent car park hunting were key to the success of the studies.The Nieuwegein study was specifically designed to test the effect of a proposed car park advisory system. VMS signs were positioned on all approaches to the town centre (Fig 2) and provided information on which car park to select (Fig 3). Based on the experience of the Town Parking Manager, the ITS system was configured to make only 20% of drivers follow the advice of the parking advisory system. This left the remaining 80% to proceed to their first choice car park, and reroute from there if itwas full.Figure 2：City centre model of NieuwegeinThe Rochdale and Takapuna models focussed on accessibility more than guidance. In Rochdale, policy decisions were used to determine car park choice, which restricted the allocation of car parks to zones, eg contract parking areas were linked to workrelated, rather than shoppingrelated zones. In Takapuna, parking was less constrained by policy and all car parks were linked to all zones with less predetermined allocation of spaces.Vehicles arriving at a car park would queue for a fixed time then move on to the next best car park based on the vehicle trip cost, walk cost, and parking cost. The Takapuna model augmented this selection process with a car park availability control and a search limit implemented through an external software controller. The search limit reflects drivers’ willingness to circulate through numerous car parks in order to find a parking space, by setting a limit on the number to be tried before giving up, and looking for something ‘highly likely’ to have spaces. The availability control monitors car park occupancy any car parks that have been full for 10 minutes are removed from the list. As soon as a vehicle leaves a car park, it is reintroduced into the selection procedure.ISSUESFirst choice car parkThe first choice car park issue arose in both Rochdale and Takapuna. This occurred when the first choice car park for a vehicle was small and quickly filled. Most vehicles that selected this car park to minimise journey costs would have to reroute to their second choice. In reality many drivers make the same trip regularly and learn that this car park is usually full. They discount it as a first choice and select a larger car park with a better chance of finding a space.Two solutions were developed to address this used their car park availability controller to overwrite the driver’s choice, to provide a proxy for the driver learning process. The second solution was to group smaller car parks, typically those with less than 50 spaces, to avoid excessively large demand being allocated to a specific car park as first choice. Car park destination catchments and walking times were adjusted in parallel to prevent too many vehicles having the same first choice car park.A high level of matrix segmentation is in use for Rochdale to allocate car parks. This methodology offers a solution through further segmentation by driver ‘familiarity’. Drivers with knowledge that the smaller car parks are full tend to avoid them and make their first choice the larger car parks.THE MODELS IN OPERATIONNieuwegeinThe base model was calibrated for a typical Saturday test scenarios included planned new developmentsin the city centre.Two future year simulations were pared. In thefirst, without the advisory system, large queues formed at the most attractive car parks. With the parking advisory system, the vehicles were more equally distributed over the available parking capacity with spaces available in most car parks. This resulted in fewer vehicles searching for a parking spot and fewer queues in the city centre. This was achieved with just 20% of drivers taking heed of the parking advisory system. Future tests will extend the range of the ITS system and redesignate some roads as pedestrian areas.As the model simulated a future year scenario of 2015 and the detailed design of the town centre will probably differ from that which has been simulated, the predicted benefits were conservatively interpreted in evaluating the scheme. Despite that, the conclusion was that an investment in a parking advisory system to make the best use of the parking capacity in Nieuwegein is justifiable.RochdaleThe Rochdale model has been used to test part of a major town centre redevelopment planned for 2012. Key features include relocating the town centre bus station and council offices, removing the main town centre multistorey car park, and redesigning key junctions on the A58 through the town centre. Further developments in the modelling process may include a similar external software controller as implemented in Takapuna and Nieuwegein. This could include explicit car park guidance at route decision points as well as a car park space ‘opportunity cost’ which would be added to the generalised cost associated with each car park before the first choice is allocated. This cost would bring the likelihood of space availability at each car park in to the destination choice although more survey data would be required to help calibrate this.TakapunaThe SParamics model for Takapuna is to be the operational transport assessment tool for all significant planning applications and district plan change proposals within central Takapuna. In this way, all assessments will be made under a mon and consistent modeling framework as has previously been successfully achieved in two other developing are