A little pre-travel mapping.

Before heading to the Tri-Cities (Richland, Kennewick, Pasco) Washington are, I spent some time comparing OSM data to Yahoo images. Most of my effort was spent aligning ways to the images, tagging bridges, adding ref= tags, and adding the "opposite" way for some motorways. I also spent time drawing parts of the PSC airport.

I don't really trust the "Richland Y" area. I'm not sure how far along the construction had progressed when the Yahoo images were taken.