The Henderson Interchange, which connects highways I-515, I-11, I-215, and Lake Mead Parkway, was constructed between 2004-2006 when Clark County, NV had a population of approximately 1.5 million residents. With the County’s population now at more than 2.2 million, the interchange is in urgent need of improvement to accommodate present and future traffic demands. The Nevada Department of Transportation, the City of Henderson, and engineering consultant C A Group are now engaged in the NEPA process for the selected “build alternative” to replace the existing interchange.

C A Group had worked with RDV Systems in earlier stages of the project and turned to RDV once again to help prepare visualization content for a virtual public meeting website. NDOT and C A Group needed an unusually high amount of visualization content.
As C A Group president Jim Caviola described, “This interchange not only impacts highway-to-highway connections, but access to several important local arterials. In earlier pre-pandemic public outreach efforts we learned that what every person wanted to see was how they would get from their own particular Point A to Point B. For our upcoming virtual Henderson Interchange Open House website, we wanted to set up drive-through videos of every possible driving route”.

RDV applied its 123BIM applications to turn the project’s Microstation and Open Roads design files into a detailed, geometrically accurate 3D virtual model of the interchange itself and of the connecting highways for several miles in each direction. RDV then set to work helping C A Group create the video content they needed. As Kevin Stewart, RDV’s Director of Operations describes –

“This project exemplifies the power and economy of RDV’s ‘Publish, Don’t Render’ philosophy. NDOT wanted videos for 17 separate driving routes totaling over 65 miles of driving, as well as several flyover clips. That added up to over one hour of video footage. Developing that much content with traditional visualization methods on a cost-per-video-minute basis would have run into the hundreds of thousands of dollars. With 123BIM it was easy to use the published 3D model to create as many drive-throughs and fly-overs as they needed, all within a couple of days”.

The virtual public meeting website went live on July 6, and included 27 videos exported from the 3D model.

Like many RDV clients whose initial focus was on visualization for public outreach, C A Group quickly discovered the value of the 123BIM model for evaluating details of their proposed design. As C A Group’s senior project manager Jim Mischler stated –

“It makes a huge difference when you can see all of the different design elements put together in an accurate and realistic 3D environment. 123BIM let us explore the entire project interactively and catch many design shortcomings and flaws early in the process. At the crossover lanes we had designed some S-curves according to AASHTO standards, but when we were able to see them from a driver’s perspective it became clear that we could make some improvements for better and safer operation. We also discovered and resolved issues with overhead signs that had looked fine on the 2D signing plan, but had problems that became obvious in the 3D environment. There were many examples of this kind of early detection and resolution”.

C A Group also opted to engage RDV to help validate certain aspects of the design by running roadway safety simulations with its Roadway Safety Audit 3D (RSA 3D) application. As RDV’s Road Safety Industry Manager Larry Mohr describes –

“RSA 3D applies AASHTO sight distance methodologies in a new way. Instead of separated 2D straight-edge analysis of vertical and horizontal centerline curves, RSA 3D steps down each travel lane and tests if the driver can see that two-foot object at the required sight distance for the design speed, taking the whole 3D environment into account. If not, it iterates until it determines the maximum safe driving speed”.

RDV used the 123BIM model to run stopping sight simulations on all travel lanes for the entire lengths of the four highways running through the interchange. According to Mr. Mischler –

“The proposed interchange includes an innovative crossover of travel lanes with S-curves, and it features a curved flyover ramp connecting I-215 and I-515. Also NDOT had recently increased the heights of their standard side barriers. With these complex geometric configurations, we wanted to be sure that we were maintaining adequate stopping sight distances for our target design speeds. We had seen what RDV had done with RSA 3D on another interchange project and thought it was ideal for our situation.”

The results were published in the form of a color-coded and annotated CAD drawing that showed the maximum safe driving speed at every location throughout the project. In addition, RSA 3D provided a detailed interactive report that let the project engineers see each location in the model to help determine the causes of sight distance deficiencies.

According to RDV’s CEO Natan Elsberg –

The analysis revealed some areas that were deficient, and C A Group was able to make adjustments and corrections to the design geometry to bring these areas into compliance. For example, the investigation of one deficient area showed an error in the way superelevation on a curve had been applied, causing two sections of roadway to join incorrectly.