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Integration of vehicle operating cost and emission models
The NZVOC model and the VEPM were reviewed in terms of each model’s purpose, scope, and data inputs and outputs and their update frequency, and common and unique elements were identified. From the review, several potential opportunities were identified to align similar aspects of the models. These include aligning the current and forecasted vehicle fleet, as well as understanding the differences between the underlying speed models and the effect of road configuration on fuel consumption and emissions. In terms of the individual models, the NZVOC model was found to be not well maintained and requires updating, particularly the fleet profile, which is currently limited to diesel and petrol vehicles. The model is also not user friendly (or available to the public), unlike the VEPM, which has been developed into an online tool. For the VEPM, there are potential opportunities to improve various aspects, including improving the effects of low speed (without an increase in stop–start conditions) and incorporating the effects of varying road configurations. It was established that users need to have greater awareness around the limitations and uses of the models (or outputs) to ensure they are appropriately used for their intended task.
Read the full report here.