In Norway, convoy driving () is used during winter in case weather is too bad for vehicles to pass on their own. Convoy driving is initiated when the strong wind quickly fills the road with snow behind snowplows, particularly on mountain passes. Only a limited number of vehicles are allowed for each convoy and convoy leader is obliged to decline vehicles not fit for the drive. Storm convoys are prone to [[multiple-vehicle collision]]. Convoy driving is used through [[Hardangervidda]] pass on [[Norwegian National Road 7|road 7]] during blizzards. Convoy is sometimes used on road E134 at the highest and most exposed sections during bad weather. On [[European route E6]] through [[Saltfjellet]] pass convoy driving is often used when wind speed is over 15-20 m/s ([[Beaufort scale|fresh or strong gale]]) in winter conditions. During the winter of 1990 there was convoy driving for almost 500 hours at Saltfjellet