On Interstate 78, which according to my landlords was built over 10 years ago they built turtle bridges. They look like a normal road bridge to connect the Wildness area on one side of the road the ponds on the other side of the interstate. The best part about the bridges is they have so much stuff that there is no way anyone could get accross.
Side Note: These bridges were not in the inital plans so after building this interstate it sat empty for 5 years until they reached a solution. BTW, I don't think the bridges are too successful. Right on the other side of the interstate is a highway that is before the ponds that will get the turtles anyway. That road has been there for over 20 years. The road is also on a steep rockwall.