PITTSBURGH (KDKA) — Starting today, the Port Authority is embarking on a new 2-year project involving the busy Mt. Washington Transit Tunnel.

The detours put in place due to the project are going to have an impact on commuters coming in and out of town.

If you plan on riding the ‘T’ or certain buses in the morning and even during the day, your service will not be disrupted.

All the work on the tunnel will happen overnight.

The tunnel will be closed nightly from 8:00 p.m. until 4:30 a.m.

The long-term project will replace the lighting and cable inside the tunnel.

According to the Port Authority, the ‘T’ and buses that use the tunnel will be detoured through the Allentown neighborhood.

To keep everything on schedule, there will be no additional stops in Allentown.

Riders should plan for trips to take an extra 10 minutes in both directions.

If you ride the ‘T’ both inbound and outbound, the Station Square stop will not be in service.

Rail shuttles to Station Square will be provided from the 1st Avenue stop.

No other stops will be impacted.

For buses, all stops will be in service.

Inbound buses will go through Allentown, while outbound buses will go through the Wabash Tunnel.

Those detours will be in place from 8:00 p.m. through 4:30 a.m.

More information on the closure, project, and details can be found on the Port Authority’s website.