We used the route arrows for one race in 2011 as did one other local RD. On roads, where there is regular vehicle traffic, they were totally gone within about 2 weeks. On the bikepath they faded out within about 6-8 weeks and were gone the next spring after the snow melted.
You can peel them up if you need.
If we had a ban on painting roads around here this is what I'd go with.