I-35 Capital Express South Project Plan – Stassney Lane to south of William Cannon Drive – Audio Transcript
The second page of the layout picks up just north of Stassney Lane. The managed lanes would go over both the Stassney Lane and William Cannon Drive bridges.
Also at Stassney Lane are the first of many intersection bypass lanes. Intersection bypass lanes are one-way roads next to and separate from the mainlanes and frontage roads that allow entering and exiting traffic to merge without disrupting mainlane traffic. Intersection bypass lanes allow traffic to bypass frontage road traffic signals at cross streets while maintaining local access.
An independent research study by the University of Texas Center for Transportation Research analyzed the existing conditions, as compared with elevating the managed lanes or leaving them at ground level from SH 71/Ben White Boulevard to south of William Cannon Drive.
The study concluded that the elevated managed lane section reduces conflict points by 81% compared to the ground level managed lane section. Furthermore, total crash reductions for the elevated managed lanes could be 20% less per year than the ground level managed lanes. For severe crashes, the elevated managed lanes could result in 228% fewer severe crashes than the ground level managed lanes.
Finally, in terms of safety cost benefits, compared with the existing conditions, the ground level section saves about $6.2 million per year and the elevated section saves about $20.6 million per year. Comparing the elevated and ground level managed lane sections, we see a reduction of 232% in all types of crash costs per year.