my f150 did that real bad on the drivers side. i just used rain x. that stuff is amazing (except for real light rain, or the mist off of other cars tires). throw some of that one regularly and you will find yourself not even using your wipers. the rain just shoots off when you are driving.
on the interstate i would just put my wipers on one of the lowest interval settings to clear the occasional mist (when its raining a decent amount, the rain clears off the mist) and cruz, even when it was raining hard.
i swear by the stuff, especially in rainy climates like florida.
