Nearly a month after Iowa’s new 60-mile-per-hour speed limit took effect, drivers in Sioux County are still adjusting to different travel speeds—and some state highways remain posted at 55 while undergoing additional safety reviews.
The new default speed limit took effect July 1 on rural highways and county blacktop roads that had previously been posted at 55 miles per hour. Gravel and dirt roads were not affected.
County Completes Sign Transition
Sioux County Engineer Joel Sikkema says the county received approximately 50 replacement signs shortly before the change took effect.
“All the updates have been made. In fact, we received our signs, I think it was on June 30, just a little before noon. And the change went into effect July 1. And by the end of the day on July 1, we had all of the critical signs replaced,” Sikkema said.
The “critical” signs were the regulatory signs displaying the new limit. The county installed additional advisory signs in the following weeks, particularly where drivers transition from 60 miles per hour into lower-speed zones. Those signs provide advance notice before the posted limit drops.
Sikkema says all county-maintained paved roads covered by the statewide change are now posted at 60. Established lower-speed zones, including those near communities, remain in place.
Why Some Roads Remain At 55 MPH
Responsibility for speed limits depends on which agency maintains the road. The Iowa Department of Transportation oversees U.S. and Iowa-numbered routes, while county engineers oversee county roads.
That means speed limits along highways such as U.S. Highway 75 are determined by the Iowa DOT rather than Sioux County.
The DOT says it has updated more than 1,200 signs statewide since July 1. However, its statewide crash-prediction system identified some road segments that require more detailed review before their limits can be increased.
Those reviews consider curves, hills, driveway spacing, traffic levels, wildlife crossings, slow-moving vehicles, crash history and other risk factors. The DOT says additional roads could receive 60-mile-per-hour signs before the end of the year.
Until then, motorists should obey the posted limit.
Sikkema says consistency among comparable county roads was an important consideration during the local transition.
“I think on our end, we feel that overall consistency in speed limits is…best for safety. I think it gets pretty tough for drivers if there’s one road that’s 55 and one road that’s 60…if they’re unsure, you can see different drivers driving at different speeds. And that’s not good for safety either,” Sikkema said.
Drivers Continue Adjusting
Sikkema says he has observed a wider range of travel speeds since the change took effect. Some motorists appear to be following their previous driving habits, while others are traveling at the new limit.
Sioux County may install additional signs to clarify speed-limit changes between county and state routes. Officials will also continue monitoring approaches to growing communities, where lower-speed zones may eventually need to be extended.
The Iowa DOT reminds motorists that even where the posted limit has increased, road and weather conditions may require slower speeds, particularly at night or during inclement weather.
B-40 Remains Closed
In a separate road-construction update, Sikkema says B-40 remains closed while work continues on its concrete overlay.
“We’re working right now to get the road open as quickly as we can. We know that it’s taken longer, I think longer than I expected, but also longer than what the public would like. But we’re making sure that we’re doing the project in a way where we’re going to get a high quality result, and we’re going to wait to open the road until it’s safe for traffic,” Sikkema said.
Sikkema acknowledged that weather has affected the project. He says concrete construction can take longer initially than some other paving work, but the B-40 overlay is expected to last 40 to 50 years based on the performance of other concrete roads.
No official re-opening date has been set.
