Iowa Notes

[Mav94]

Iowa does a pretty good job of blurring the lines between expressway and non-Interstate freeway. Which I appreciate; speed limits notwithstanding, I think that once signals and high-traffic intersections are removed in favor of interchanges and overpasses, there are better uses of funds than full freeway conversion.

That said, I know at least US 61 between Davenport and DeWitt does not allow farm machinery (Street View Link). I assume other longer full-freeway segments such as US 20 from Fort Dodge to Waterloo and US 218 south of Iowa City have similar restrictions, but I don't know what the length threshold is or what other roads would qualify.

I fully agree that many times an expressway with limited at-grade access is enough or more than enough for a road like US 20 in Iowa. The truck traffic is heavy enough to warrant the four-lane road but the overall traffic doesn't justify fully controlling the access, with all the bridges that would have to be built to let farmers move machinery.

The Des Moines Beltway notoriously does allow farm machinery because it crosses the Des Moines River.

(Also the continuous freeway section of US 20 ends at the Iowa 17 exit south of Highview; it doesn't quite make it to Fort Dodge. I only know this because I'm from the area originally and once had to make a blind left from 20 to Webster County P73 in a blizzard when I could almost see to the front of my car!)

[kphoger]

So the difference between some two lane state routes and the US 20 freeway will be 5 mph. I don't know of any states that allow 60+ on two lane roads that also don't allow 70 on non-interstate freeways

Minnesota doesn't have any non-interstates posted at 70.

I should point out that MnDOT could theoretically set a speed limit of 70 mph on a non-Interstate freeway, even if it weren't a trunk highway.

Transportation
Chapter 169 — Traffic Regulations
§ 169.14 — Speed Limits, Zones;  Radar
Subd. 4 — Establishment of zones by commissioner

On determining upon the basis of an engineering and traffic investigation that any speed set forth in this section is greater or less than is reasonable or safe under the conditions found to exist on any trunk highway or upon any part thereof, the commissioner may erect appropriate signs designating a reasonable and safe speed limit thereat, which speed limit shall be effective when such signs are erected. Any speeds in excess of such limits shall be prima facie evidence that the speed is not reasonable or prudent and that it is unlawful; except that any speed limit within any municipality shall be a maximum limit and any speed in excess thereof shall be unlawful. On determining upon that basis that a part of the trunk highway system outside a municipality should be a zone of maximum speed limit, the commissioner may establish that part as such a zone by erecting appropriate signs showing the beginning and end of the zone, designating a reasonable and safe speed therefor, which may be different than the speed set forth in this section, and that it is a zone of maximum speed limit. The speed so designated by the commissioner within any such zone shall be a maximum speed limit, and speed in excess of such limit shall be unlawful. The commissioner may in the same manner from time to time alter the boundary of such a zone and the speed limit therein or eliminate such zone.

Transportation
Chapter 169 — Traffic Regulations
§ 169.14 — Speed Limits, Zones;  Radar
Subd. 5 — Zoning within local area

When local authorities believe that the existing speed limit upon any street or highway, or part thereof, within their respective jurisdictions and not a part of the trunk highway system is greater or less than is reasonable or safe under existing conditions, they may request the commissioner to authorize, upon the basis of an engineering and traffic investigation, the erection of appropriate signs designating what speed is reasonable and safe, and the commissioner may authorize the erection of appropriate signs designating a reasonable and safe speed limit thereat, which speed limit shall be effective when such signs are erected. Any speeds in excess of these speed limits shall be prima facie evidence that the speed is not reasonable or prudent and that it is unlawful; except that any speed limit within any municipality shall be a maximum limit and any speed in excess thereof shall be unlawful. Alteration of speed limits on streets and highways shall be made only upon authority of the commissioner except as provided by law.

[Great Lakes Roads]

New bypass coming to US 30 in Missouri Valley.

[CtrlAltDel]

New bypass coming to US 30 in Missouri Valley.

Originally planned with 4 lanes, it will now have 2.