SAN ANTONIO – Drivers on the far North Side are set to receive some long-awaited traffic relief this summer, but it will require one more major construction phase.
The Texas Department of Transportation (TxDOT) is converting the intersection at Blanco Road and Loop 1604 into a diverging diamond interchange (DDI), the first of its kind in the San Antonio area.
The design will temporarily shift traffic to the left side of the road as drivers head onto Blanco Road over the main lanes of Loop 1604, allowing easier, faster turns without a dedicated signal.
The new configuration is expected to improve safety and ease congestion along one of the region’s busiest corridors, according to TxDOT. Similar interchanges are already in use at several locations across Texas.
“A traditional intersection has 26 points where you could potentially have a crash. And a DDI only has 14 points at the intersection where you could potentially crash,” TxDOT Spokesperson Jennifer Serold said. “So we’re cutting those crash potential points by almost half.”
The project is entering its final construction phase. Beginning in March 2026, drivers will see a new traffic pattern as the intersection transitions into the DDI configuration.
The full interchange is expected to be complete by late summer 2026.
As part of the transition, TxDOT plans to close Blanco Road at Loop 1604 for a weekend in late March for a permanent traffic switch.
“We will have one weekend where Blanco Road will be closed while we switch traffic in the area,” Serold said. “It’ll open back up at 5 a.m. on Monday morning, and that’s when you will see the new traffic configuration on Blanco.”
During this phase, traffic on Blanco Road will shift left as it crosses Loop 1604. Traffic on the Loop 1604 frontage roads will need to use bypass lanes.
Temporary signals will be in place, and barriers will be installed to build concrete islands. Pedestrian access may be limited, and weeknight closures will continue as needed.
Serold said the changes are designed to make travel easier in the long run while maintaining access to nearby businesses and shopping centers.
“The big changes will come to drivers on Blanco Road as they cross 1604,” she said. “But the important thing is that it’s going to make it easier in the long run, and also, your access to businesses and shopping centers will not be affected by this.”
TxDOT is urging drivers to slow down, obey posted signs and remain alert while traveling through the work zone. The exact date and time for the traffic switch will be announced once it is confirmed.
For more information about the Loop 1604 North Expansion Project and the diverging diamond interchange at Blanco Road, visit TxDOT’s website.
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