IH 35 at SH 80 and IH 35 at SL 82 Innovative Intersections

San Marcos, Texas

Our firm designed the traffic signal (two locations) to include the initial timing/phasing for the first displaced left turn (DLT) signal in Texas. CONSOR Engineers modeled the DLT in SYNCHRO and, in coordination with TxDOT, developed the initial timing/phasing plan which helped TxDOT determine the additional detector racks/load switches needed to accommodate the phases. The challenge was to integrate these signals into the City of San Marcos’s signal network which uses Siemens controllers (ACTRA software) and have the provisions in the cabinet to accommodate the load switches required for the large number of overlaps. We coordinated with TxDOT/City to install pedestrian poles with audible pedestrian signals, median islands, wheelchair ramps and crosswalks at the appropriate locations meeting the current ADA criteria. We provided intersection signing and pavement markings for the innovative intersections. Temporary signals and additional illumination was provided to accommodate the complicated phases of construction due to the complex conversion of a diamond to a DLT. Our firm provided construction phase services and helped in fine tuning the signal timing/phasing after the initial field implementation. We identified probable design/construction issues early on so that no surprises are encountered in field.