San Antonio Opens Loop 1604 Diverging Diamond as $218M Expansion Moves Ahead
Key Highlights
- The new diverging diamond interchange at Loop 1604 and Blanco Road is now open, with city leaders calling it an early success in reducing congestion.
- Phase 4 of the Loop 1604 project, a $218 million expansion between U.S. 281 and Redland Road, is about 35 percent complete and expected to finish next year.
- TXDOT is addressing driver concerns about signage and road markings, with updated striping and visibility improvements planned through 2028.
Just weeks after opening, the new diverging diamond interchange at Loop 1604 and Blanco Road is already changing the way drivers move through San Antonio’s Far North Side, and city leaders say the biggest improvements are still ahead.
The latest traffic pattern switch went into effect Monday, March 23, as part of the ongoing construction work.
At a packed town hall, city officials and the Texas Department of Transportation outlined what comes next along Loop 1604, one of the region’s most congested corridors, according to News4SA.
The newly opened interchange is part of a broader, multi-phase overhaul designed to ease bottlenecks and keep traffic moving as the area continues to grow.
A diverging diamond interchange briefly moves traffic to the left side of the road at a traffic light so drivers can turn left onto the highway without having to wait for a separate left-turn signal.
The design reduces conflict points compared to a traditional intersection and is used in several U.S. states to improve flow and safety once drivers become familiar with the pattern.
Now the focus shifts east. Phase 4 of the project targets Loop 1604 between U.S. Highway 281 and Redland Road. The $218 million effort is about 35 percent complete and on track to finish next year.
“Segment four is about 35% complete,” District 9 Councilwoman Misty Spears said during the town hall, as reported by News4SA. “Infrastructure is one of our top priorities for San Antonio, for all cities, and that is definitely a top priority for me in District 9.”
Drivers at the meeting pressed officials about confusing lane markings and signage at the new interchange. TXDOT representatives said updates are underway, including clearer signs and refreshed striping.
A separate project to improve road markings and make them easier to see will continue through 2028.
Spears said early signs are encouraging. After years of heavy backups at Blanco and 1604, traffic has begun to move more smoothly.
According to TxDOT project planning discussed at the meeting and referenced in News4SA coverage, the Loop 1604 expansion is being delivered in phases to spread out construction impacts across the corridor rather than closing or heavily disrupting large sections at once.
Source: News4SA