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Partnership makes dangerous intersection safer

Aerial view of the improved intersection of the Chickasaw Turnpike and State Highway 1 near Fitzhugh. [PROVIDED]
Aerial view of the improved intersection of the Chickasaw Turnpike and State Highway 1 near Fitzhugh. [PROVIDED]

Changes to an intersection where the Chickasaw Turnpike connects with Oklahoma State Highway 1 near Fitzhugh transformed motorists’ trepidation into peace of mind.

This once dangerous intersection allows cars to exit the turnpike safer than ever before, according to partners in the project.

The turnpike and SH 1 come together to form a T intersection. A stop sign at the end of the turnpike governs the traffic, so cars must come to a complete stop before turning onto SH 1.

The T intersection is on a 3-degree horizontal curve on SH-1. Both the turnpike and SH 1 originally consisted of two lanes with shoulders to the side.

The curve, along with the road’s 7.5% cross-slope, made the intersection dangerous and contributed to a high rate of fatal crashes. In a three-year period beginning in 2014, the intersection had four fatal crashes, all of which involved vehicles leaving the turnpike and turning onto SH 1, which had a posted speed limit of 65 mph.

The number of fatal crashes got the attention of officials from the Oklahoma Department of Transportation.

“This was an intersection that was sure popping up often on ODOT’s radar, so they reached out to the Oklahoma Turnpike Authority and the Chickasaw Nation to see if we could do something to make it safer for drivers,” said Darian Butler, director of engineering with the OTA.

The OTA, ODOT, and Chickasaw Nation formed a partnership to fund a project for improvements to the intersection. All three entities had a vested interest in the project: The OTA is responsible for all work done on the Chickasaw Turnpike, ODOT oversees SH 1, and the turnpike is located in the Chickasaw Nation’s tribal jurisdiction.

Olsson, an engineering and design firm with offices in Oklahoma City and Tulsa, was tasked to complete preliminary and final design for improvements on the intersection. Working with Olsson’s team of engineers, led by project manager Jimmy Sparks and lead designer Derick Millican, the partnership agreed to widen SH-1 to add dedicated left- and right-turn lanes with appropriate storage and deceleration length and regrade drainage ditches along both roadways.

Olsson also incorporated right-turn channelization, separating the right-turn lane from the adjacent through lane with striping. The channelization provided for much earlier separation of vehicles turning right from those continuing through on SH-1, which should also make it easier for stopped vehicles coming from the turnpike to determine if approaching vehicles are turning or continuing through. The channelization also helped neutralize the effects of the steep pavement cross-slope along the curve.

The design included several new signs, including warning signs and a stop sign with in-panel flashing lights; transverse rumble strips on all three approaches; and LED lighting improvements.

The speed limit through the intersection was lowered to 55 mph.

These design features were all aimed at improving safety and reducing crashes.

“Reducing the speed from 65 to 55 mph will have a major impact,” said Millican, Olsson’s designer. “This is a difficult intersection to navigate, especially from the turnpike as you approach the stop-controlled intersection. Lowering the speed limit should help make the driving task simpler.”

The design widened both roads without acquiring more land, which kept the overall cost and time required for construction low.

The Cummins Construction Company of Enid completed the project on time.

The changes appear to be working. Nine months after the intersection was completed, no major accidents were reported. Traffic is moving more smoothly than before.

“If we can make infrastructure improvements to potentially save someone’s life or save someone from an injury, I think that means a lot,” Millican said.

Final cost for the project was approximately $1.6 million and was split three ways. The OTA’s Butler believes the project would have still been built without the partnership, but joining forces helped get it done sooner rather than later.

“It was done right with the partnership,” he said.

This article is sponsored by Olsson.