The I-35E/I-35W Merge Through Denton Is Closing—Periodically, and the Pattern Isn't Done

If your Friday night or Saturday morning starts with a drive north through Denton, this weekend already handed you a surprise. The I-35E/I-35W interchange—the bottleneck every Flower Mound commuter knows on a first-name basis—went into a rolling closure that started Friday evening and ran into Sunday morning.

This was not a one-off. It is a preview of the next three-plus years.

The work is part of TxDOT's ongoing $583 million project to improve the I-35E/I-35W merge, with the project expected to be completed in Fall 2029. That's the timeline. Not months—years. And each construction phase requires pulling ramps and main lanes offline in pieces, with relatively short notice before each closure window.

Here's what hit this past weekend specifically. The southbound I-35E off-ramp to southbound I-35W closed from 8 p.m. Friday to 10 a.m. Saturday, and the northbound I-35W off-ramp to northbound I-35E closed during the same window. Then it kept going. All southbound and northbound lanes of I-35E from Oak Street to Bonnie Brae Street closed from 8 p.m. Saturday until 9 a.m. Sunday, though frontage roads remained open. Northbound and southbound Bonnie Brae Street under I-35E also narrowed to one lane during that same window.

The pattern is deliberate. TxDOT tends to shut down one direction on one night, then come back and do the opposite direction or a different nearby segment later in the week to keep the overall work moving. That means no single closure is the last one. The next one is already being planned.

The full scope calls for widening I-35 in Denton County from 4 to 6 lanes and upgrading ramps and frontage roads, including rebuilding the I-35E/35W interchange and expanding frontage roads from 4 to 8 lanes. Serious reconstruction. You don't rebuild an interchange at that scale without periodically eliminating the ramps that currently exist.

The project is weather permitting, so if rain or other weather moves into the area, the work can be pushed back to a later date—which sounds like a relief until you realize it just delays the closure to a week when you're less prepared for it.

For Flower Mound drivers, this merge is the funnel. Anyone heading to Denton, north on I-35W, or catching I-35E toward Dallas passes through it. When the main lanes close, the service road becomes the only option through that segment, which means slower speeds, tighter merges, and backups that can build quickly if traffic is heavier than usual.

What to do right now: bookmark DriveTexas.org and follow @TxDOTDallas on X. Closures are typically announced a few days out—not weeks. Signed detours will be in place during closures, but TxDOT advises commuters to expect delays and plan for extra travel time. If your job has flex hours and you pass through that interchange on weekday nights, ask about them now rather than after the first night you sit on the service road for forty minutes.

This project will deliver real improvement—eventually. The interchange around UNT has been a chokepoint for decades, and the finished version will be genuinely better. But "Fall 2029" is a long way off. The inconvenience is not a glitch. It's the cost of the fix.