The paper presents the main modelling results from the AKTA road pricing experiment in Copenhagen, Denmark. The main part of the experiment involves 2x200 car-users equipped with a GPS-based device in their cars. The participants' normal travel pattern is estimated on observations from a control period. The corresponding payment for a given road-pricing scheme assuming they do not change behaviour can then be calculated. The idea in the experiment is then that the participants are paid the money they save by changing behaviour. Each scheme is applied over an 8-week period for each participant. And each participant is tested with two schemes plus a control period. The participants are distributed in a factorial design among income groups, commuting patterns and schemes. Since realistic and planned levels of road pricing are tested, the experiment is as close as possible to a real scheme. The expected amount of savings lies between zero (if negative, payment is ignored) and 5000 Danish KR. per participant for each scheme (0-600 Euro). Two pricing schemes were zone-based with four different levels per km. with the most expensive in the inner city, and the cheapest in the suburb. Furthermore, the pricing varied between the peak and non-peak hours. The third scheme was a toll-based system with payment for zone crossings. The GPS-device calculates dynamically the pricing level, and for a given trip the participant can see the total cost. Furthermore, the coordinates are locked each second. This information is matched to digital maps (roads, intersections and origin/destinations of trips), and also compared with automatic traffic counting stations. This provides a unique dataset concerning route choices, speed, congestion, and speed-flow relationships. Due to experiences from an earlier project, goal oriented schemes were rejected, e.g. road-type dependent charging (most expensive in local streets, less at motorways outside the city, etc.) or charging marginal costs. This was decided due to problems in the participants understanding too complex pricing schemes, due to technical problems (map matching the GPS-device with an acceptable speed and security/precision), and due to the time-schedule of the project (software validation issues). The selection of participants followed a rather complicated procedure in a stratified factorial design. The participants completed a questionnaire before the experiment, and another after (among other things to test whether they changed attitudes). Furthermore, the 200 users also answered a stated preference survey before the experiment. Besides supplementing the field experiment, this makes it possible to validate stated preference as a method towards the field experiment. Furthermore, selected participants took part in qualitative focus group interviews. The paper presents the main results of this fairly comprehensive road pricing experiment. Conclusions are made on the direct traffic and economic impacts of the different pricing schemes, road users attitudes before and after road pricing is implemented, and the accuracy of different survey and modelling techniques. For the covering abstract see ITRD E124693.
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