Rome, December 31 - Italian Industry Minister Corrado Passera said in a release on Monday that as of January 1, 2013, tolls on some of the country's highways will increase an average of 2.91%. The cost hike was calculated per highway and based on 2012 traffic averages. Increases will vary according to the stretch of highway. The motorway from Milan to Rome and Naples will go up 3.70%. The sharpest hikes will apply to motorways in the region of Veneto, up 12.63%, specifically the stretch around the city of Mestre up 13.55%, and the ring highway in the Val d'Aosta region up 14.44%.