I-37 Southbound Shut Down at I-35 Near Downtown San Antonio After Crash, Traffic Rerouted

Closure disrupts one of downtown’s key freeway connections

Southbound Interstate 37 was closed at the interchange with Interstate 35 near downtown San Antonio after a crash, forcing drivers off the main lanes and triggering a cascade of delays on nearby routes. The closure affects a critical connector used by commuters moving between the city’s East Side, South Side and the downtown core, as well as motorists transferring between major interstate corridors.

Authorities diverted traffic away from the closure area while emergency crews responded and worked to secure the scene. As with similar incidents at complex downtown interchanges, the operational priorities typically include medical response, clearing disabled vehicles, documenting the crash, and addressing roadway hazards such as debris or fluid spills before reopening lanes.

Why this location backs up quickly

The I-37/I-35 junction sits within a dense web of ramps and merges that already compress traffic during peak periods. When a closure occurs at this node, congestion often spreads beyond the immediate interchange as vehicles are redirected onto frontage roads and parallel surface streets. Drivers trying to rejoin the freeway system can encounter slowdowns at on-ramps and signalized intersections not designed to absorb sudden, freeway-level volumes.

Downtown traffic conditions can also be influenced by ongoing construction schedules and lane restrictions on adjacent segments of I-35 and nearby ramps. Even when a crash is the immediate cause of a shutdown, work zones and narrowed lanes can reduce the network’s ability to recover quickly once traffic is rerouted.

What drivers should expect and how to navigate

• Expect significant backups approaching downtown on southbound I-37 and on routes feeding into the I-35 interchange.

• Plan for reduced speeds on frontage roads as detoured traffic competes with local access, bus stops and turning movements.

• Allow extra time for trips that depend on transferring between I-37 and I-35 near downtown, particularly during commute windows.

• Use posted electronic message signs and official traffic maps for real-time lane status and reopening updates.

When a freeway closure occurs near downtown interchanges, delays often expand rapidly because detours funnel into a limited number of city streets and ramps.

Reopening depends on investigation and cleanup

The timeline to reopen southbound I-37 at I-35 depends on factors such as whether injuries required extended medical response, whether vehicles must be towed from travel lanes, and whether investigators need time on the roadway. If the crash damaged roadside hardware, barriers or signs, crews may also need additional time to make repairs before traffic can safely resume at normal capacity.

Motorists are urged to slow down near the scene, follow detour instructions, and avoid stopping on shoulders or ramps except in emergencies.