By Josh Siatkowski | Staff Writer
Eliciting horror stories of lane closures, orange cones and time-consuming detours, it’s not easy to think of I-35 construction as remotely interesting. But alongside the typical lane expansion and access road improvements of the My35 Waco South project is a novel piece of road engineering.
For the last decade, the My35 Waco projects have meant traffic and lane closures, followed by repavement and expansion across 14 miles of interstate between North and South Loop 340. Now, the Waco South Project — the third and final stage — is underway.
Beginning in February 2025 and lasting until 2029, My35 Waco South works on the three-mile stretch of I-35 between 12th Street and South Loop 340. Along this stretch, crews will widen I-35 to eight lanes, reconstruct overpasses and bridges and complete various other work on sidewalks and on-ramps and off-ramps. Also, at Valley Mills Drive, the project will add a novel intersection design, according to Jacob Smith, Waco TxDOT public information officer.
“The new intersection will be constructed into what’s known as a diverging diamond intersection,” Smith said. “If you travel around Texas, you encounter many of these that have been built in Austin and College Station.”
First described in a graduate paper in 2000, the “diverging diamond intersection” sounds like something out of a civil engineering action movie. Since the first one was built in Missouri in 2009, DDI’s have grown in popularity, with over 200 completed across the country. While they’re complicated enough to best be demonstrated in a short video, the simple explanation is that these intersections convert traffic into two one-way streets, allowing drivers to turn left onto the interstate without waiting for cars to pass in the opposite direction.
“It will improve the intersection by reducing the number of potential crash points, reducing wait times at intersections, reducing maintenance costs and providing capacity for future travel demand,” Smith said.
For avid users of I-35, like Boise, Idaho, junior Joe Simeri, the introduction of a diverging diamond intersection is a victory. Simeri often drives on I-35 and Valley Mills for local commuting, on road trips and in his job as an ambulance driver. In each of these capacities, he looks forward to reaping the benefits of the new interchange.
“Diverging diamonds have always been my favorite style of interchange when linking major arterial routes to freeways,” Simeri said. “Diverging diamonds shift traffic to the left side of the road temporarily, eliminating the need for a left-turn signal. They also increase safety by reducing the number of potential conflict points between different traffic as well as between vehicles and pedestrians.”
His only issue is the time it takes to get to this holy grail of highway engineering. For the time being, traffic is worse, not better.
“As a Waco driver, the traffic surrounding the Valley Mills intersection when accessing H-E-B is my biggest complaint,” Simeri said. “Due to the absence of the old northbound on-ramp and the closure of lanes forcing more traffic on frontage roads, this significantly slows my travel times when going to any businesses on Loop 340 or Valley Mills. But it makes sense given the amount of work being done.”
Unfortunately for Simeri, other students and frequent visitors of the Valley Mills H-E-B, Smith said that Valley Mills will be impacted on and off until the completion of the larger project in 2029.
“The intersections of Valley Mills Drive and I-35 will have varying degrees of impacts to traffic throughout the entire project,” Smith said. “Demolition of the current direct connection and the reconstruction of the Valley Mills bridges will be performed during this time.”
For up-to-date information and announcements on the My35 Waco South Project, visit here.
