WI: US 18/US 151 Alternate in Fitchburg

[the_spui_ninja]

Noticed a very well signed US 18/151 Alternate in Fitchburg, following US 14, CTH MM, CTH M, and CTH PB.
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Are these not in the HB because they're similar to the alternate interstate routes WI has? This seems more like a traditional US Alternate route to me.

[Highway63]

Wikipedia says it's a permanently signed detour, which I would say is equivalent to the "Emergency Detour" or "Alternate" for interstates that some states sign.

[neroute2]

The source doesn't really back that up though. It seems to be signed no differently from any other alternate route.

[SSOWorld]

"Alternate" routes in WI (and IL and IN for that matter) are just their signage for "Incident Bypass" routes (The "official" MUTCD spec). Only one exception exists in Ashland.  Thus these are to be omitted.  They're used on busy routes where a crash or road work can bottleneck it real fast  Almost all of the Interstates around cities or on high-traffic volume routes.

[the_spui_ninja]

"Alternate" routes in WI (and IL and IN for that matter) are just their signage for "Incident Bypass" routes (The "official" MUTCD spec). Only one exception exists in Ashland.  Thus these are to be omitted.  They're used on busy routes where a crash or road work can bottleneck it real fast  Almost all of the Interstates around cities or on high-traffic volume routes.

I was wondering if that was some weird Wisconsin thing, thanks for clearing that up!