## Learn more about the algorithm we use to calculate footprints in the category transport, which data sources are used and which we plan for the future.

### Calculations for transport

We calculate the transport footprint by considering car journeys, public transport (train, bus and tram) and flights separately.

To calculate the footprint for car use, we use data from the Motor Vehicle Registry on vehicles per household. Then we use data from Statistics Norway on average kilometres driven per year for different types of vehicles for a given municipality to calculate passenger kilometres travelled by car for each household. Finally, we use a factor for CO2e emissions per passenger kilometre to find the footprint.

The factors for CO2e emissions for car use are based on both average direct emission data for each municipality from the Motor Vehicle Registry, as well as indirect factors that take into account the entire life cycle of the car. We assume that cars are bought and used in an average lifespan (200,000 km), and include the costs of car production distributed over the life of the car in our calculation. Our factors for emissions related to owning and driving a car are largely based on this EU report.

The footprint of public transport is currently based on Statistics Norway's data on travel per capita in various areas, combined with Telia’s mobility data on train, tram and boat use. The SSB data is used to find total passenger kilometres per year with different public transport methods on a national level for bus, train, tram and boat travel. For bus travel, this is divided up based on SSB’s data, allocating kilometres to specific counties and municipalities. For train, tram and boat data, we allocate kilometres to different municipalities based on Telia’s mobility data, which shows different rates of movement by each form of transport. We then convert these figures to footprints using CO2 intensities.

The footprint of flights abroad is currently based on Avinor’s data for Norwegian inhabitants, which averages out to 1.46 European flights a year and 0.23 cross-continental flights per year. Our domestic flight estimates use these numbers but integrate Telia’s mobility data in order to provide estimates on a municipality level.

This gives a number of passenger kilometres travelled for each person, which we in turn link to CO2 intensities for flying. The factor for CO2 emissions for aviation comes from DEFRA's factors for direct emissions, combined with an altitude factor that describes the increase in radiant power at altitude, and an indirect factor that explains emissions related to the production of aviation fuel. It is important to emphasise that at present the footprint for flying is the *same *for all Norwegians - we need a better data basis before we can say anything else.

### Data sources for transport

We use direct emission figures for the Norwegian car fleet from the Motor Vehicle Register, together with indirect life cycle figures for production, maintenance and end-of-life for cars, to find emission factors that are specific to each municipality. We combine this with statistics on mileage per year and per car type from Statistics Norway to calculate the footprint of car transport in each municipality.

We also collect data on the use of public transport from Statistics Norway, and mobility data from Telia regarding transport by train, tram, boat and plane, which we combine with emission factors to calculate the footprint of public transport.

In the future, we will collaborate with public transport and airlines to obtain regional travel data.