Method to Identify Optimal Land Use and Transport Policy Packages: a Comparison of Cba and Indicator Based Optimisation
G Emberger, S Shepherd, ITS, University of Leeds; X Zhang, TRL, UK
City authorities require a tool to identify city specific optimal Land Use and Transport strategies to meet their future needs and targets. The methodology presented here is based on an ongoing UK research project, where it is applied and tested for eight cities. The main idea is to connect traditional steps, which have to be carried out to identify optimal strategies and to automate their interaction, and thus to find optimal city specific solutions. To be able to do so a series of initial steps in collaboration with the cities have to be done.
1. Definition of city specific objectives and scenarios including population growth rates, economic development etc.
2. Set up of a city specific LUTI-model (Land Use Transport Interaction model) based on information defined under point 1 like city specific zoning system, inhabitants, workplaces, housing etc.
3. Definition of a set of policy instruments and their city specific ranges to be tested.
4. Agreement on a city specific Assessment of impacts realized through the translation of the objectives defined under point 1 into so called objective functions.
If the steps 1 to 4 are carried out the optimisation process can start. The loop Combination of policy instruments ? LUTI-model run ? Assessment of Impacts ? New Combination of policy instruments is carried out until no ?better? combination of policy instruments. These iterations are the optimisation process. The number of policy instruments, their spatial and temporal disaggregation and the complexity of the method to assess the impacts determine the number of iterations.
As policy instruments we consider instruments for Pedestrians (Pedestrianisation), Public Transport (New PT-Infrastructure, Fares, Frequency), Private Car (New Roads, Road Pricing, Parking charges, Road capacity increase/decrease, Fuel tax, Parking supply), and Land use measures (Controls on development, Land use charges). In this paper we present results for two different LUTI models SPM (Sketch Planning Model) and TPM (Transport Policy Model) which operate at different levels of detail. The LUTI models provide information about land use and transport system developments for a 30 year period. This information will be used to appraise the impacts of the applied instruments against city specific objectives using first a Cost Benefit Analysis (CBA-approach) where all impacts are monetised and second an indicator/target (I/T-approach) based approach where the objective function is a weighted sum of ?level of goal achievement? for a set of outcome indicators. The results of these two approaches will be compared for SPM and TPM models of Edinburgh and Leeds.
Association for European Transport