When converting an in-bay to a mini tunnel makes financial sense
An industry consultant lays out the engineering, market, and cost factors self-service operators should weigh before boosting throughput with a short conveyor.
By The Car Wash News Staff
3 min read
In-bay automatic systems generate a large share of self-service operator revenue, but their capacity ceiling can cap growth. For operators bumping against that limit, converting a bay into a mini tunnel is one path to higher throughput, according to analysis by Robert Roman for Auto Laundry News.
The piece cites ALN research showing in-bay sales account for more than 52 percent of operators' total income, with volumes trending at roughly 18,000 to 20,000 cars per year. Touchless in-bays typically wash 8 to 15 cars per hour, and friction units 10 to 15. A mini tunnel, by contrast, can process up to 50 cars per hour, offering a compact alternative to adding a second in-bay or a whole new structure.
Reading the market before you build
Roman stresses that engineering feasibility is only half the question. Operators must confirm their local market can absorb the added throughput. Signs of unmet demand include long wait times, frequent balking, and drive-offs. Beyond those qualitative cues, a market area analysis is needed to judge whether the supply and demand balance in the trade area supports the investment.
A conversion is described as a strategic shift, not just an equipment swap. It reshapes the business model by changing the target market, pricing, staffing, and site economics. The mini tunnel aims to deliver the speed and consistency of a full express exterior wash in a smaller footprint, but operators must overcome customer hesitation about conveyors versus gantry systems. Success typically means moving away from low-price, pay-per-use transactions toward premium tiered packages and monthly memberships. That shift often requires a full-time employee or site manager, more housekeeping, and added maintenance.
Equipment, permits, and costs
A mini tunnel conveyor runs 40 to 60 feet with five to seven brushes plus a tire brush, high-pressure wheels, wax and rinse arches, and a tire shiner. Conveyor options include over/under chain, surface mount, single belt, and dual belt, with cost differences between chain and dual belt measured in tens of thousands of dollars.
Roman advises keeping the building's exterior dimensions unchanged where possible, since that speeds planning and zoning approval and avoids the need for a conditional use permit. Zoning reviews commonly examine traffic, queuing, parking, drainage, and environmental impacts, and some municipalities require traffic or environmental studies when volumes are expected to rise. Extensive plans raise start-up costs. A similar installation cost $600,000 ten years ago, though reusing existing utility, foundation, and site infrastructure can lower the bill.
To test whether the numbers work, Roman points to the debt service coverage ratio, calculated as net operating income divided by annual debt service. He recommends a DSCR of 1.5 or higher as a basic sanity check before committing to a full feasibility study.
Why it matters for operators
Self-service operators facing capacity limits have a genuine decision to make, and this analysis frames it clearly: throughput gains only pay off if real unmet demand exists in the trade area. Before spending on a conversion, operators should quantify wait times, drive-offs, and local market saturation rather than assuming faster wash speeds will fill themselves. The move also demands a business model change, from transactional pricing to memberships and premium packages, along with new labor and technology costs. Running a DSCR check and a pro forma before contacting equipment suppliers can prevent an expensive retrofit that the market cannot support.
