Category: North-Central

Crashes near Aht’wy Plaza have become too frequent of a sight for those who drive past them or see them on the news. Too many of them have ended with a loss to our community.

While it is not a new area of concern for drivers on US-12 near the Clearwater River Casino and Lodge, many have been motivated by two recent deaths to offer their own solutions.

Several have been considered by the Idaho Transportation Department as the area developed, but these inquiries provide an opportunity to clarify why certain actions have or have not been taken.

LOWERING THE SPEED LIMIT

Although this seems to be the easy answer, lowering the speed limit may not be the best solution.

Speed limits are generally determined by how fast drivers comfortably and naturally move in the area, usually set at a pace described as what is “safe and reasonable.” They are safest when the majority of drivers are traveling the same speed, which is why ITD conducts speed studies to determine the speed at which 85 percent of drivers are traveling at or below before establishing a limit.

Speed studies are typically prompted by changes to the area, including new businesses opening and fluctuations in traffic patterns, as well as requests to adjust any speed zones. Five studies have been conducted near the casino since its opening by both the Nez Perce Tribe and by ITD, with the earliest study occurring in 1997 and the most recent in October 2018. ITD has also met with the Idaho State Police multiple times to analyze crash data.

To date, these discussions and drivers’ speeds have not supported changing the limit, and without either a serious commitment of law enforcement resources or a serious change in roadway conditions, reducing the speed limit would not be effective in improving safety or slowing traffic to or from the area.

While vehicles moving at lower speeds would impact each other with less force, that would only be the case if all drivers were moving at that lower speed limit. But if one driver was following the lower, posted speed limit and another was moving at the natural pace allowed by the road, additional conflicts could arise.

The greatest concern is that some drivers would obey the slower posted speed limit and others would not. As these drivers encountered slower vehicles, they would likely make more abrupt and unpredictable movements (like last-minute lane changes), which could increase the crash rate.

Most crashes at the entrances have been related to exiting drivers failing to yield to oncoming traffic when turning left. Variation in vehicle speeds through the area would likely make that left turn tougher—with some vehicles approaching at lower speeds and others at higher speeds, it would be difficult to judge a safe gap in traffic.

ITD has repeatedly investigated the safety and appropriateness of the posted limit, with each study supporting the current limit to prevent a possible increase in crashes.

INSTALLING A SIGNAL

If most crashes are related to drivers experiencing difficulty turning left, then it is reasonable that a signal could improve safety.

Just as speed limits are set a certain way based on data collection and analysis, signals are normally installed at specific locations once shown to be warranted.

Signal warrants are based on a variety of engineering factors, including how many vehicles make which turning movements. Although an engineer’s judgment can influence the final decision, these warrants are the primary basis for signal installation to ensure that traffic continues to flow smoothly.

Signals should only be installed when warranted as they typically increase certain kinds of crashes, including rear-end collisions.

Data collected from the entrances in 2012 did not support installing a signal or merit interrupting the flow of traffic on the highway.

IF NOTHING ELSE, CLOSING ACCESS

ITD uses access agreements all over the state to ensure that new or changing developments near highways do not create safety or mobility issues for drivers.

In the case of the casino, access to US-12 was initially provided by a county road which already had an agreement in place. When the county transferred the road to the casino in 2000, it altered its use, prompting a fresh access agreement.

A traffic impact study performed near the time of the development of the access agreement proposed an interchange as the ultimate solution, especially given expansion plans for the facility. It also outlined smaller improvements that could be implemented in the meantime to keep up with the growth of the facility and traffic to it while design continued on the interchange.

The tribe agreed to these terms, giving ITD the authority to restrict access if the commitments were not met. In the intervening years, some phased improvements—such as lighting, turn bays and acceleration lanes—have been constructed, but the final commitment remains unfulfilled.

Rather than close access and hinder productive relationships, ITD chose to work as a partner to the tribe. The department has remained involved in the design process, providing input on the development of the interchange to guarantee it will meet standards when incorporated into the public transportation system. ITD has listened to the tribe’s concerns, granted extensions when necessary and helped aid environmental discussions needed to complete the proposed interchange.

THE LONG-TERM SOLUTION

Although development of the interchange has been delayed for a few years as the tribe encountered environmental issues common to this type of project, they have funded other improvements proposed by ITD in the meantime, including the construction of a concrete island and the placement of additional signage in the area in the last year.

In January, a team of diverse professionals will meet to examine the data—all refreshed in the last month—as well as driver behavior to identify any and all solutions.

The best solution remains—and has always been—an interchange, but the road safety audit aims to determine effective steps that can be implemented immediately. ITD will work with the tribe to carry out any viable solutions the team recommends.

The interchange’s design is set for completion next winter, with construction following the tribe’s procurement of funds.

Construction of the interchange will reduce the possibility and frequency of crashes. Engineering and enforcement can help improve safety, but only engaged drivers can truly ensure safety while accessing and using the highway.

As early as February, ITD engineers were reaching out to the public to discuss a major undertaking for US-12 this season: two bridge replacements and 50 miles of paving.

That’s no small amount of work for the highway that follows the Lochsa River through abundant U.S. Forest Service lands and provides access to popular fishing spots and hot springs; it also gives the trucking community a scenic shortcut into Montana as it winds its way up to Lolo Pass.

Used by locals and tourists alike, this two-lane highway would see significant work and miles of orange barrels for the first time since 2000. ITD cautioned all drivers that working on so much in the remote location could lead to delays upwards of two hours.

“There are not many places to pass in the corridor, and with all of the summer traffic it normally sees, we definitely wanted to overstate delays rather than understate them,” project manager Janet Zarate said. “Thankfully, we were able to keep delays at 60 minutes or less all summer.”

ITD specifications limit delays through projects to 30 minutes, but the contractors working in the corridor phased the work to improve their efficiency and further minimize delays. Hotspots installed specifically for the projects provided connectivity that enabled project staff to promptly address any issues with delays.

Creative thinking also led to a partnership with Three Rivers Rafting out of Lowell, which ITD hired to shuttle bicyclists through the work zones.

“This partnership makes sense because at that time of year, the river doesn’t run as high, and there are fewer rafters,” resident engineer Joe Schacher said. “During their season, these companies routinely shuttle their customers up and down the river, and we didn’t see a reason for that to end this year. They have the right equipment, and we could give them an opportunity to economically benefit from construction.”

According to the rafting company, the shuttle operated for nine weeks and hauled 263 bicyclists who were visiting from all over the country and the world.

The service did not go unnoticed by the Adventure Cycling Association, which organizes some of those trips and was contacted personally by ITD engineers prior to construction.

In a letter to ITD, the association commended their efforts, which they said may be a model for construction managers in other states to follow to accommodate their groups.

As ITD engineers found ways to ease the impact of construction, they were also able to work with operations to advance more projects, including a preservation project between the two paving jobs.

In total, more than $17 million was spent to replace two bridges and resurface roughly 55 miles of US-12.

“We appreciate the patience of drivers who encountered us on the roads all summer,” Zarate said. “Now we look forward to years of driving on an improved highway.”

Nearly twenty years later, the Goff Bridge—better known as the Time Zone Bridge near Riggins—remains one of a few tied-arch bridges in Idaho.*

But its unusual design is not the only thing that makes it unique.

The distinctive bridge stands out due to the dedication of several ITD engineers who oversaw its successful replacement, which began in 1996 and lasted until 1999.

At that time, Dave Kuisti was not yet the district engineer but was graduating from ITD’s Engineering in Training Program.

“I moved to the maintenance yard at Lucile for more than two years to be the project engineer,” Kuisti said. “My wife wasn’t particularly thrilled about the location.”

Located on US-95, the Goff Bridge would be a challenge to replace. The structure, built in 1935, spanned the Salmon River and served 2,000 vehicles per day, as well as 12 river outfitters in nearby Riggins.

The new structure would have to withstand consistent pressure from a slow landslide at its south end, be tall enough to stay above high water and wide enough to accommodate two trucks crossing at once.

To maintain mobility for the traveling public on the state’s primary north-south route during the construction of this three-year project, the design and construction teams planned to temporarily relocate the original structure to serve as the detour. It was the best option given the absence of an alternative route and the close confines of the canyon.

Hydraulic jacks and an estimated 72 hours would be required to move the 1.24 million-pound steel bridge to its new location 65 feet to the west. At that time US-95 would be completely closed to traffic through Riggins, prompting ITD to stipulate stricter penalties should contractor Harcon Inc. cause additional delays.

A 1996 Spokesman-Review article quoted Kuisti as saying that he felt “pretty confident” that the structure would not fall into the river. In a follow up article in 1997, public affairs specialist Ralph Poore mentioned the engineers’ eagerness to transition to the next phase of the project and described the construction challenge as “the kind of thing that makes and breaks careers.”

To advertise the closure, ITD placed notices all over the state, and even out of the state in Lolo, Montana, which sits on US-12 just across the state line. In the end, US-95 was reopened 36 hours ahead of schedule.

Watch a video of the relocation.

Robert Gordon, the lead inspector involved with surveying the area for the relocation of the bridge, said he was relieved when it went as smoothly as it did.

“It was a very critical move,” Gordon said. “If anything went wrong, the state was basically cut in two and would require a 500-mile detour to get from South Idaho to North Idaho.”

“It was not without its own tribulations,” Kuisti said. “In the end though, we got a pretty amazing structure that will be there long after I’m gone.”

According to its latest inspection, the Goff Bridge will likely last another thirty to fifty years.

*The Goff Bridge was the only tied-arch bridge in the state until the Shoup Bridge over the Salmon River was built last year south of Salmon.

We know this summer’s construction has been less-than-convenient for many drivers, and knowing that there’s still several weeks of construction ahead, we would like to take the time to say thank you for your patience and cooperation.

Recently, the department received thanks about its efforts to support all users during construction from a local bicycling association. To read that letter, click here.

These words of gratitude mean a great deal to ITD as our project managers have worked hard to oversee these projects that will improve your safety and mobility along this corridor.

Any time we receive feedback, we try to respond or adjust our practices when possible. While planning construction this summer, we heard that this corridor was a popular bicycling destination and worked to reduce our impact. The result was a partnership with Three Rivers Rafting to offer a shuttle, which is noted in the above letter from the Adventure Cycling Association.

Once again, thank you for your patience, and please continue to reach out with any comments or concerns.

Beginning the week of August 27, crews will work to improve fish passage at Moose Creek near Elk City by replacing an aging culvert under Idaho Highway 14.

The old culvert is not large enough to accommodate the flow of water and allow fish to easily pass.

“At high water, the flow is constricted and funneled into the circular pipe, creating higher velocities like a spigot,” said Miranda Main, a project manager for the Watershed Division within the Nez Perce Tribe. “The culvert is currently considered a barrier to migration for spring chinook and steelhead, but the replacement should open access to upstream habitat.”

Main said all life stages of fish would be able to swim upstream, with other features of the new culvert providing them areas to rest.

This project was designed by ITD and is funded by the Nez Perce Tribe and the U.S. Forest Service.

Debco Construction will replace the culvert in the next two months for $500,000. During construction, travelers should expect alternating, one-way traffic through the work zone.