There are two possible models for building the Maya II line extension: one with a metrobus route, and the other through a regular metro. The difference between these two decisions is 135 million euros. That is: 480 million if the line is built using conventional light rail and 345 million if using hydrogen buses on a dedicated track. The line will connect Asprela in Porto with the airport. We are talking about a route with a length of 13.3 km and 16 stations (in the case of metro construction) and 14.3 km and 18 stations (in the case of metrobus construction). If a metro route is chosen, 6.3 km is planned to be overground, 4.3 km via viaduct and 2.7 km via tunnel with four underground stations. If it is a “metrobus”, all stations will be on the surface with viaducts: one between Hospital S. João II and Pedrusos, another between Giesta and S. Djemil (crosses the Leixões line and will have an overground station), another one to Caverneira (crosses the A4 motorway ) and another between Aguas Santas and Mileiros (on the A3 motorway and the Lesa River). The S. Mamede line, between IPO and Estádio do Mar, will have an estimated cost of $258 million and parking for 500 cars.