In Nariño, a few kilometers can change everything. One tunnel near Pasto often decides whether a trip feels smooth or painfully slow, especially for cargo and long-distance travelers heading through Colombia’s southwest.
In late October 2025, that tunnel reopened after months of repairs, bringing traffic back to a key corridor that many drivers use daily.
There was still one rule to keep in mind: traffic flowed again, but nighttime closures remained scheduled through the end of December 2025.
Why repairs mattered
The tunnel had a long list of issues, including persistent water leaks that affected the structure and demanded a full treatment of both the floor and the roof along the tunnel’s length.
Water leaks inside a tunnel are not just annoying, they can create slippery spots, reduce visibility, and trigger bigger damage over time. That is why stopping leaks is a safety job first, and a comfort upgrade second.
Engineers also addressed a geological fault inside the tunnel, a risk that could threaten safety for drivers and passengers if left untreated.
To strengthen the most critical area, a 45-meter section was reinforced, and the intervention included demolition, excavation, and replacement of slabs in the base, known as the solera.
Instead of one massive shutdown, the work was divided into eight modules, a practical way to manage a complex job while keeping crews safer and pushing progress faster.
Timeline and restrictions
The intervention started on July 21, 2025, on the stretch between PR18+0430 and PR20+0140, a segment treated as a high-risk point needing urgent stabilization.
After that shutdown, traffic returned on October 26, 2025, restoring a route that helps move vehicles between Pasto and the wider southwest region.
Even with the reopening, a nightly closure was set from 7:00 p.m. to 6:00 a.m., beginning November 1 and lasting through December 31, 2025.
To avoid the nightly shutdown, drivers should aim to pass before 7:00 p.m. or after 6:00 a.m. That schedule runs through December 31, 2025, so arriving near closing time can quickly turn into a long wait.
The restriction aimed to protect users while remaining tasks and finishing works continued, so drivers could benefit during the day without exposing crews and travelers to unnecessary nighttime risk.
What it cost, in context
The repair package was valued US$5.5 million, including construction and oversight, a significant investment for a single piece of road infrastructure near a busy city.
Money aside, the real payoff is reduced risk. Fixing leaks and stabilizing weak sections lowers the chance of sudden closures, costly emergency works, and accidents tied to structural failures.
By September 2025, the works were reported at 92% completion, a sign the project was already in its final stretch before the October reopening.
What drivers should do now
For regular drivers, the simplest move is timing. Daytime trips avoid the 7:00 p.m. cutoff, and they also reduce the chance of getting stuck behind long cargo lines.
For freight operators, dispatch windows matter even more. When several trucks arrive close to closing time, queues grow fast, and delays can wipe out the tunnel’s usual time savings.
Local mobility also benefits when heavy traffic uses the tunnel instead of pushing into slower urban routes. Around the reopening, local statements referenced roughly 5,000 vehicles per day using this corridor.
This episode is a reminder that maintenance is not a minor detail. Water and geology can damage a tunnel quietly, and once that happens, everyone pays through delays, detours, and higher risks.
The road is open again
The Daza tunnel reopening in October 2025 restored a key connection near Pasto, improving daily mobility and easing pressure on surrounding routes.
With night closures running until December 31, 2025, the route still requires planning, but the corridor is open again and built to be safer for the thousands who depend on it.