The move, announced in July, sees a number of motorways, including the A22 in the Algarve, covered by the discount.
The government decided to implement the reductions in order to increase mobility in economically disadvantaged areas across the country.
The Algarve, while wealthier than most regions in Portugal, was grouped with poorer regions due to its importance as the country’s primary tourist destination, while the EN125 road is not deemed as a viable alternative to the A22 motorway.