Interest in the project was rekindled in the late 1970, when the subsea Vardø Tunnel was planned and later built. The choice of a subsea tunnel alternative would allow for major costs savings, easily shaving away half the cost. Another contributing factor was the Oslo Airport location controversy, which proposed various locations for a new airport. A fixed crossing would be allow for a fixed service from Vestfold and Buskerud if an airport was located in Hobøl or Ås, and it would allow for a fixed service from Follo and Østfold if the airport was located in Hurum. Also the construction of a new plant at Tofte Cellulosefabrikk was expected to give a large rise in lumber transport to the region and could contribute to cross-fjord traffic. Previous analysis had been based on traffic data collected for other uses, so in 1980 a dedicated traffic survey was carried out.