Interstate 35 in San Antonio to Close Nightly Oct. 26-30 as Expansion Work Continues San Antonio motorists will face nightly detours along I-35 from Oct. 26-30, 2026, while construction for the I-35 Northeast Expansion Program proceeds. Main lanes remain open, but frontage roads and several exits will close during low‑traffic hours to support widening and bridge upgrades. Drivers traveling on Interstate 35 in the northeastern region of San Antonio should anticipate nighttime road closures and alternative routes during the week of October 26 to 30, 2026, as part of the ongoing I‑35 Northeast Expansion Program. The Texas Department of Transportation (TxDOT) announced that several segments of the I‑35 frontage roads and main lanes will be closed each evening, weather dependent, to allow construction crews to work on widening, bridge improvements and other upgrades designed to increase capacity and safety along this critical corridor. The nightly shutdowns are scheduled from nine o'clock at night until five in the morning on Mondays through Thursdays, and from eleven at night until seven in the morning on Fridays.Nightly Closure Hours and Detour RoutesThese hours correspond with the period of lowest traffic volume, thereby minimizing congestion. During these times, the northbound I‑35 frontage road between Space Center Drive and Rittiman Road will be locked out. Drivers traveling north along this frontage road will be required to exit onto Industry Park Drive, return via the next entrance ramp, and subsequently use designated detour routes that meander through local streets such as Fratt Road, Eisenhauer Road, and Center Park Boulevard.For those intending to reach the main I‑35 lanes, exits 164 B and 165 will also be closed, forcing motorists to use alternate ramps and side streets to maintain access to key destinations like the Border Patrol's regional office and the nearby Hill Air Force Base. Southbound traffic will experience comparable restrictions.The frontage road south of Fratt Road, including Exit 165, will close nightly, compelling southbound drivers to detour through Fratt Road, Interchange Parkway, and Walzem Road, and then re‑enter the frontage road past the closure point. Similar measures apply to the southbound I‑35 exit routes 162 and 164 B, which will be sealed during the scheduled windows.Preserving Traffic Flow During ConstructionThis comprehensive network of detours aims to preserve a reliable flow of vehicles while facilitating critical construction work, particularly on newly planned bridge components that will support additional lanes and improved structural integrity. During the closure period, the I‑35 main lanes will remain open to ensure that long‑distance traffic can traverse the corridor with minimal interruption. Access to major local facilities, such as the Brooke Army Medical Center and the Binz‑Engleman Road service area, will also be maintained.Motorists are encouraged to consult TxDOT's real‑time traffic updates, plan alternative routes in advance, and allow additional travel time to accommodate detour distances. The Department has published a detailed map on its website showing the exact detour paths, including the use of Walzem Road U‑turns, Eisenhauer Road connections, and the southbound I‑410 connector ramps.Failure to adhere to the posted detour signage may result in loss of access or delays, as some junctions will be permanently closed during the construction window. The I‑35 Northeast Expansion Program, a multi‑year initiative aimed at addressing traffic bottlenecks and enhancing safety, includes the addition of two new lanes in each direction, upgraded interchanges, modernized bridge structures, and improvements to pedestrian and bicycle pathways.Project Benefits and Driver Compliance TipsAccording to TxDOT, the project is expected to reduce travel times, lower accident rates, and support the economic growth of northeastern San Antonio by improving connectivity between residential neighborhoods, industrial parks, and key public facilities. The nightly closures thus represent a temporary inconvenience that will ultimately contribute to a more efficient and safer transportation network for all road users. The Department advises drivers to heed posted signs, use the TxDOT mobile app for live updates, and follow detour instructions closely.Failure to comply with detour routes may result in inadvertent entry onto closed segments, leading to further delays and potential safety hazards. By following the recommended alternative paths, motorists can help ensure that construction crews can complete essential work safely and that the overall project timeline remains on track.