11.2 Calculation model
NTMCalc supports several calculation models. There are two major models: a) shipment transport where emissions generated by a vehicle are allocated to the shipment in proportion to its use of the total carrying capacity, and b) vehicle operation which calculates the gross emissions generated by running a vehicle. Within each model there are several options for input data, e.g. shipments can be sized by volume, weight, etc, and vehicle operation by distance or consumed amount of fuel. All models are not available for all types of vehicles, e.g. shipment size in tonne-kilometres cannot be applied to air freight since emissons per tonne is not linear to the distance (distance and cargo weight must be entered as separate figures).
Transport of people. It is assumed that passenger transports are undertaken in a shared transport system where the capacity of a vehicle (or set of vehicles) can be shared between multiple passengers or groups. A passenger (or group) is therefore only allocated the part of the emissions that emanates from its share. The allocation formula is: Allocation_factor = Number_of_passengers/Passenger_occupancy The gross emissions of the vehicle are multiplied by the allocation factor to calculate the share of the passenger (or group).
Passenger transport (passenger-kilometres)
Passenger transport, allocation and size determined by transport effort in passenger-kilometres. See “Passenger transport” for details about allocation principles.
Vehicle operation (distance)
Calculation of gross emissions generated when running/operating the vehicle a specified distance. No shipment is specified and no allocation is done; the system will ask for the cargo load factor but this is use for emissions calculation only (the larger the factor, the larger the emissions)
Vehicle operation (fuel)
Calculation of gross emissions generated when running/operating a vehicle on a specified amount of fuel. No shipment is specified and no allocation is done; the system may ask for the cargo load factor but this is use for emissions calculation only (the larger the factor, the larger the emissions)