Document Type

Conference Paper

Publication Date




Publication Title

Procedia - Social and Behavioral Sciences





Conference Name

Transport Research Arena - Europe 1012


Alternative road pricing schemes are promising strategies to alleviate congestion and other environmental problems related to urban and regional road transportation. However, in practice, environmental issues are not often taken into account, especially at regional level. In 2010, due to the financial crisis in Portugal, several tolls were introduced in some motorways that were previously financed by the government. One of these cases was the A29 motorway, which connects the cities of Aveiro and Oporto. After the introduction of tolls about 50% of the Average Daily Traffic shifted to alternative routes or modes. This paper discusses the impact that tolls had on route choice, and evaluates the consequences in terms of emissions and energy use on the road network after tolls were implemented. Experimental tests were conducted during off-peak and peak periods before and after toll implementation. Vehicle dynamics were measured using a high-sensitivity GPS data logger. Using more than 10 000 km and 174 hours of data, a micro-scale methodology based on the Vehicle Specific Power (VSP) concept was used to extract second-by-second emissions in four alternative routes. The changes in traffic distribution caused by the introduction of tolls did not cause a significant impact in terms of emissions factors on the alternative routes. However, the findings indicate that the diversion of traffic from A29 to local roads implies an increase in CO2 emissions and a reduction in local pollutants emissions such as CO and NOx.


Open access under CC BY-NC-ND license.

Original Publication Citation

Bandeira, J., Coelho, M., Pimentel, M., & Khattak, A. (2012). Impact of intercity tolls in Portugal – an environmental perspective. Procedia - Social and Behavioral Sciences, 48, 1174-1183. doi: