One of the most frustrating things about the freeway system in Portland is how poorly placed the navigational signs are. The signs noting which lane goes towards what freeway often appear only as the lane is actually splitting off from the main stretch (a problem for strangers to the city - like me - who either have the option of cutting across 4 lanes within 50ft or taking our chances and trying to reverse navigate back), or they appear only once several miles before the lanes merge off so it's easy to forget what goes where. Most freeway systems will warn you both 1-2 miles and 1/4-1/2 mile before the split, and then will have each lane clearly labelled when the split actually does occur.