Private equity did not spend billions of dollars buying and building automated car washes on prime suburban corners because they loved clean cars. They acquired and built them because an express tunnel wash is a commercial real estate arbitrage playing dress up as a convenience service. Between 2020 and 2024, private equity firms poured billions into rolling up car wash operators like Mister Car Wash, Driven Brands, and Zips. The physical asset looks like a simple retail building with rotating brushes. The financial engine relies on real structural mechanics. The subscription model shift has been widely adopted across the economy. The traditional car wash relied on sunny weekend weather. If it rained on Saturday, weekly revenue could fall by 60% in some cases. The modern express tunnel shifted almost entirely to an unlimited membership club. Customers pay $25+ per month on automatic credit card recurring billing. The customer visits an average of 2.5 times per month. The variable cost per wash in electricity, water recycling chemicals, and soap is around $1.50. Once a facility signs ~3,500 active members, membership fees alone cover 100% of the location's monthly operating costs, debt service, snd payroll. Every retail drive up customer after that is almost pure profit. These car washes also have minimal labor overhead. Traditional car washes required 15-25 employees vacuuming interiors, wiping windows, and drying trunks by hand. An express tunnel runs with two or three entry level employees on site. Customers can pull up, scan a barcode, and ride the conveyor belt. Customers vacuum their own cars under self serve canopies. Labor costs drop from 35% of revenue to 12% to 15%. Owners of these car washes also receive bonus depreciation. Car washes are classified under tax code Section 168(k) we special purpose commercial real estate property rather than standard retail buildings. The building structure and the specialized tunnel machinery qualify for a 15 year recovery period instead of the standard 39 year commercial property depreciation schedule. When developers take 100% bonus depreciation, an operator investing $5 million into a new build could write off a massive portion of the total project cost in year one, wiping out millions of dollars of active taxable income across their portfolio. These owners are also masters of the sale leaseback model. These developer acquires onto two acres of prime highway adjacent dirt, builds the tunnel, stabilizes the wash club memberships, and then sells the underlying real estate to a real estate investment trust. They execute a 20 year absolute triple net lease at a 5.75% to 6.25% cap rate. The sale leaseback pulls out 100% of the developer's initial equity plus millions in profit, while the operating entity keeps collecting the recurring monthly cash flows from the memberships. The retail customer thinks they are getting unlimited car washes for $30 / month. The operator built a recurring software type margin on cheap water and traded the underlying dirt for an upfront cash out. Genius!