Determination of safe speeds for a coach travelling on a floating bridge

• Vehicle deviation from the path increases with the bus speed and storm severity. • The coach does not stray from the traffic lane under mild storm conditions W1 and W2. • At a speed of 90 km/h for W6 and W7, the vehicle leaves the traffic lane frequently. • At a speed of 90 km/h for W8, W9 and W10 the bus is not stable. • At a speed of 108 km/h for W6-W10 the bus is not stable. Coastal highway route E39 is immense road project in Norway with the aim to shorten the journey time between the south part (Kristiansand city) and the north part of the country (Trondheim city). Different high-tech structures will make E39 route continuous and reduce the travel time from currently 21 h to 11 h. A floating bridge has been considered for Bjørnafjorden. This paper suggests bus safe speeds for travel on a floating bridge exposed to 10 different storm conditions (W1–W10). The results show that the coach does not stray from the traffic lane under mild storm conditions (W1–W2) even for the highest vehicle speed of 108 km/h. However, at a speed of 90 km/h for W6 and W7 and at a speed of 72 km/h for W8, the vehicle severely and often departures the traffic lane. At 36 km/h, 54 km/h and 72 km/h for strong storms (W9–W10), the windward rear wheel of the bus frequently loses contact with the floating bridge deck.