A subsystem like a dryer is a set of elements, which is a system itself (arch, producers, nozzles, starter), and a component of a larger system (automatic carwash bay).
So, decision about dryer depends on system (carwash) requirements.
For example, high traffic sites usually merit high volume carwash systems like in-bay express format (60’ long). Here, dryers are free-standing.
Lower volume sites have shorter wash-bay design, typically 38’ or 50’. 50’ has free-standing dryer to increase likelihood of washing more cars per hour than 38’ bay.
38’ wash-bay can accommodate on-board or free-standing.
If goal and objective is drying quality, contour design is suggested. Contour design is available as on-board with some carwash systems and free-standing.
If goal and objective is cars per hour, free-standing is suggested because it decreases time on machine and people may spend less time driving through. Here, a contour design could help improve dry quality.
If goal and objective is drying quality, on-board with contour design is suggested because it takes consistency and quality out of hands of motorists.