STREAM Passenger Transport

The STREAM passenger transport project (Study on TRansport Emissions of All Modes) reviews the current air-pollutant and carbon emissions of passenger transport and makes projections for the year 2020. One of the fruits of this research is a model that calculates vehicle emissions on the basis of emissions-abatement and logistical parameters . (There is also a STREAM project on international freight)Is it better to go by rail for that holiday trip, or will a well-occupied car have a similar environmental impact ? This depends on the vehicles employed  and their emissions abatement systems, logistical parameters and the emissions of interest (CO2 or air pollutants, for example).

The STREAM passenger transport project was developed in cooperation with key stakeholders, including the Dutch ministry of Infrastructure & Environment, the Foundation for Climate-Friendly Procurement and Business (SKAO), MilieuCentraal, the Stimular Foundation and Dutch Rail (NS).

The STREAM model calculates the emissions of the various transport modes (car, train, bus, plane ), making due allowance for a range of relevant variables. The study focuses on greenhouse gases and air pollutants like nitrogen oxides and particulates.

Technologies Logistics
Fleet-average emissions Distance
Specific technologies Prior and onward journeys
Emission standards (e.g. Euro 5) Route
Fuel type Scale
Uniform emission factors
Because of differences in assumptions and methodological choices, there is considerable variation in the emission factors used by companies and other organisations for calculating carbon footprints. In close collaboration with a team of experts, CE Delft  has developed a widely accepted and scientifically robust list of emission factors.

Generic application

The study  is frequently used by policy-makers, industry, researchers and consultants for carrying out footprint calculations, modal shift calculations, designing  more benign public transport  and a cleaner vehicle fleet. A typical example is comparison of the CO2 or particulate emissions of commuter transport from The Hague to Delft by alternative means. The emission factors used also factor in power plant emissions. The report  includes five illustrative calculations for short, medium and long distance journeys.

Specific applications

With the STREAM  model, emission factors can be customized to specific situations, incorporating user characteristics, fleet vehicle emissions classes or number of plug-in hybrids, for example. The model also calculates trends in emission factors up to 2020 on the basis of new technologies, government policies and logistical optimisation.