You could also think about upgrading your IBA to compete with the tunnel. There are a lot of new things on the market that can fit in your IBA area and compete with a tunnel for speed. Tunnels are there because people want quick in and out and don't want to do anything. If you can match that on your site, you can take a chunk out of their business instead of letting them take yours. The new POS systems will do monthly washes and everything the large tunnels are doing, most without the employee expense.
Check out
https://www.autobriteco.com/car-wash-equipment/conveyor-tunnel-system
Disclaimer: This only works for a high traffic area and I work for the company that is producing this equipment.
I think it is the best on the market and was designed to help you compete with the tunnels going in. If you want more info contact me and I can help with some traffic analysis and what kind of numbers you might bring for the location of your wash.
