Guys I dont recommend sealing car wash lots. I own 2 washes and I also have a sealing and striping business. One of the biggest issues with our parking lots is tire shine! Also wax's, and protectants that we use are all over our lots. Most sealers are water based products. They cant stick to the asphalt. Coal tar(water based) is the best product to use, outlawed in many areas of the US. This is the longest lasting product, it smells, it has a bluish finished look. Best application would be first coat brushed, second coat sprayed. But any areas that have a lot of tire shine or any other wax, silicone it really doesnt matter how you put it down its going to lift. A good asphalt job used to last 20+ years, now they use so much millings in asphalt it does not bind together like it used to. If you get 15 years from a new lot thats good. I will only spray my lot if at the end of the season I have to empty my tank. Ball park prices should run from .10-.15 per sq. ft. to have a decent size lot done. Whatever you do dont let them spray an oil based product on your lot. It will turn wet areas into skating rinks. They will have different names, gilsonite, rejuvinator etc. In the business we call it gypsy juice. beware!! Good luck and I am only sharing some of my knowledge of doing sealing for over 15 years.