Does It Still Make Sense?

I know that street cleaning is not done twice a week on every street, but in my area it is. The purpose of street cleaners/sweepers is to make the streets cleaner, or at least that is what one would imagine. Frequently, however, the streets they traverse are still dirty at best and the dirt that was once on the ground becomes airborne, frequently hitting innocent passerby in the face. But there is more. What comes along with this "sweeping" is alternate side of the street parking. The process of finding a parking spot in many areas can be rightfully called an ordeal, only made more tenuous by alternate side of the street parking restrictions. So my question is this: Does it still make sense to have street cleaning twice a week?

P.S. - Some consideration for ceasing garbage truck operations during rush hour would also be greatly appreciated.