In the June letting is a signage project labeled “statewide” but is entirely in Polk County, in two locations: the west and northeast (or east) I-35/80/235 mixmasters. The signs that look like mile markers will say “Ramp” at the top instead of “Mile” and have separate codes for each traffic movement. The codes with comment are as follows:
West Mixmaster
- I-80 eastbound ramp (the two-lane exit): Mile 123, which is only half a mile long in this direction; these markers will have A/B/C/D shaded like tenth-miles.
- I-80 westbound ramp (WB-to-NB): Mile 123, with standard tenth-mile markers; 123.0 is at the fork for EB 80 and SB 35, and 124.0 is where EB 80 and SB 35 merge.
- I-35 thru lanes: Mile 72, with Mile 73 being about where EB 80 splits off, and 73.1 NB-only just before the I-80 EB ramp joins.
- 72A/72B/72C: Presumably, since these are the exit numbers on I-35 (EB 235, WB 80, University Avenue), they’re skipped in ramp codes.
- NB 35 to EB 235: 72D
- WB 235 to NB 35/80 before 80 joins: 72E
- EB 80 to University Avenue (after 235 ramp joins, but before merging into 35): 72F
- NB 35 to University Avenue: 72G
- EB 80 to SB 35: 72H (but physically almost as far as you can get from G). This should be an I-80 code IMO.
- SB 35 to EB 235: 72I
- NB 35 to WB 80: 72J
- WB 235 to SB 35: 72K
- WB 235 to WB 80 (thru lanes): 72L
- EB 80 to EB 235 (thru lanes): 72M
- I think L and M should use either 80’s or 235’s digits, since this section is where the main east-west lanes switch designations. Since 235’s 0.0 is where the mainlines cross each other, it would technically be in negative territory! “Mile negative point 3” would be too weird. They could have been 122A/B/C or 0.0A/B/C.
Northeast Mixmaster
I-80 mile 137 is now used in all four directions even though certain ramps can and IMO should be keyed to I-35 (as Exit 87) and I-235 (as Exit 14). This means, for example, “Exit 137A” applies to not only 80’s exit to SB 235, but also NB 235 to EB 80 and SB 35 to EB 80. I-235 is labeled north/south below for travel direction.
- Unlike with I-35, there is no “Exit 137C” but the designation is skipped anyway.
- NB 235 to EB 80: 137D
- NB 235 to WB 35/80: 137E
- I think these two should be keyed to I-235 instead.
- WB 80 to NB 35: 137F
- SB 35 to WB 35/80: 137G
- I would consider this I-35’s southbound mainline.
- SB 35 to EB 80: 137H
- WB 80 to SB 235: 137I
- EB 80 to NB 35: 137J
- I would consider this I-35’s northbound mainline.
- EB 80 to SB 235: 137K
The east mixmaster’s ramp signs will have a limited lifespan, if the re-engineering of its design begins in 2023 as scheduled.