Does anyone know what the average distances are on the US expressways from fence to fence? How much shoulder? How wide are the lanes? Lets just say two lanes each way. How wide is the strip between the lanes? I know it varies widely in places but is there an average?

average approximate

average highway lane width =21.5metres (approx 12 ft)
average median width of 12.2 metres =(40 ft)
shoulders minimum required 4 ft each