The Speed Prediction Model for Heavy Vehicles
Trude Toerset, SINTEF, NO
The Norwegian speed prediction model is made to calculate realistic speed for heavy vehicles based on road geometry. The project which was completed in early 2011 was funded by the Research Council of Norway.
The speed prediction model for heavy vehicles is based on a large quantity of GPS speed reported data and geometry data made available from the National Road Data Bank by the Norwegian Public Roads Administration. The speed prediction model uses geometry variables to calculate realistic speed, and could be included in any route guidance system, and also potentially be combined with and make use of other more dynamic data.
The speed prediction model is now going to be implemented in a range of systems, including the national freight transport model, the CBA tool used by the Norwegian Public Roads Administration, heavy traffic information system including a route guidance system in which route choice algorithms are based on realistic speed prediction provided by the model described here. The speed prediction can be updated on the way if some of the dynamic conditions changes. The model will also provide valuable information to planning activities within the road administration, in giving input to design conditions, maintenance operations (like frequency) and accident prevention.
The speed is calculated in steps and each step has a sub model. The starting point is the chosen speed on flat straight roads. This is reduced as a consequence of narrow roads, small horizontal radiuses, or roads going uphill or downhill. The sub model calculating resulting speed from uphill vertical curvature uses total weight and motor engine power as input. If such data are not available, average values are used.
Norway is a country with hills and fjords, which have given challenging road curvature, especially on rural roads. Use of the model for the Norwegian road network is necessary in route choice algorithms, in order to get realistic speed predictions, but could also be valid for other countries.
Association for European Transport