The Boston Globe by Adam Vaccaro

That grinding commute over the Tobin Bridge is about to get even slower.

Beginning in April, the state will begin to close lanes on the northbound side of the bridge, followed in May by more closures in both directions where Route 1 winds through Chelsea on a viaduct. The closures are necessary to repair and repave the bridge and viaduct and will last through much of 2020.

State officials aren’t exactly sugar-coating things: It’s going to be messy — and not just around the Tobin.

“Vehicle backups are expected to extend onto the I-93 ramps, along the Leverett Connector, and towards Rutherford Avenue,” the state said in a news release this past week.

And during the morning commute, the Chelsea viaduct work could cause backups stretching as far north as the Route 60 rotary.

State officials are asking motorists to use public transportation if they can during the work and said the MBTA will run additional Blue Line service. The T is also offering some free bus rides in Chelsea, where many commuters have worried about backups from the construction affecting the popular 111 bus that goes over the Tobin and into downtown.

Inbound riders will be allowed to board without paying at four Chelsea stations of the new Silver Line branch, which runs on a bus-only road through the city toward Boston.

The Chelsea nonprofit Green Roots had pushed the T to cut fares on the 111 as well during construction. Associate executive director Maria Belen Power said she will still push for 111 discounts but noted the free Silver Line rides are at least a positive step.

“I do feel like this is more than we had before, and any economic relief to transit riders in Chelsea is welcome,” she said.