The safest answer is separate bike infrastructure. Full Netherlands style.
http://www.aviewfromthecyclepath.com/2011/11/first-cycle-sup...
http://www.aviewfromthecyclepath.com/2011/11/first-cycle-sup...
Near Zaandam there are a couple of really nice examples of this, bike detours easily 1 km for what would have been 200 m at best without the detour. (Onramp of A8, both sides).