Carwash or car wash?

Rensselaer has three car washes. The one below is on North McKinley. The sign says Northside Carwash, but the telephone directory lists it as Kennedy Autowash.

A second car wash is part of the Family Express gas station and convenience store complex in the College Square Mall. It only has the autowash bay, not the bays for hand washing.  I wonder who thought of placing the old street lights around the building.

Finally, the PDA Inc. Car Wash behind McDonalds seems to be the largest of the three. I could not find any mention of it on the Internet.

There is a bit about car washes here. It is still a mom-and-pop industry, an industry that has not been overrun with franchisers.

I do not use car washes because I do not care if my car is dirty or clean. I have heard that one reason to wash your car is to get the road salt off. I can see that for some people it might be important to have a clean car to make a good impression. Obviously car washes are used quite a bit in Renssleaer if the town supports three of them. Why do so many people spend money to wash cars? And is it carwash or car wash?