` :::::I think it's a coincidence that they're that close, though not necessarily that they're in the same area. 171-174 were assigned in the SLC area in 1935; when 173 was reassigned in 1965, the other three were still there (in fact 174 was deleted the same day that 173 was reassigned). I've noticed in other places that UDOT likes to ``cluster`` similar numbers: 105/106, 116/117, 201/202.  `