Planning to drive in Portugal? You now need an electronic device loaded with pre-payment on some sections of motorway. Temporary devices are available for €27 and top it up with deposit of €10 payments which expire after 90 days. You can get it at motorway service areas or post offices. If you're renting a car, best check whether it is fitted with such a device already. Alternatively you could just avoid the following stretches:
Norte Litoral - A28: Auto-estrada do Litoral Norte (Littoral North-highway - between Porto and Vilar de Mouros/Caminha)
Grande Porto - - A4: Porto/Amarante-highway (between Matosinhos and Águas Santas); A41: Circular Regional exterior do Porto (Porto Regional Outer Circular); A42: Alfena-Lousada-highway
Centro - A17: Littoral Center-highway (between Mira and Aveiro); A25: only on the sections between Esgueira and Angeja (Aveiro area); A29: Auto-estrada da Costa de Prata (Costa de Prata highway between Estarreja and Vila Nova de Gaia).