The old Highland Railway line from Inverness to Thurso used to maintain snow fences along the side of the line which were, I believe, very effective. They were also connected to the old mechanical semaphore signals so that if they (the fences)were blown down, the signals would automatically be returned to the danger position in order to protect oncoming trains (what is know in the business as fail safe operation. What kind of protection would you get on today's roads th that extent?:

http://www.highlandrail.org/info-lines-far_north.htm