Construction on Boston's Commonwealth Avenue Bridge is now underway. The bridge that spans a portion of the Mass Pike is closed for the next two weeks. This morning marked the first rush hour that it was closed. Reporter Bob Seay spoke with WGBH News' Craig LeMoult about how things went and what to expect going forward. The following transcript has been edited for clarity.

Craig LeMoult: So you were out there this morning at the Comm. Ave. bridge. What did you see?

Bob Seay: Well it was relatively quiet because they're getting prepared to demolish the old western side of the bridge that they're going to be replacing over the next two weeks. And they have barred all vehicular traffic on Comm. Ave. except for local traffic. Also, there are special shuttle buses that are running along with regular MBTA buses. Plenty of bicyclists and pedestrians, but no cars. And so far, state officials tell me that things are going very smoothly, but they also warn that it is early.

LeMoult: OK, so the Comm. Ave. bridge is closed to cars, but open to pedestrians and bikes. What about the BU Bridge, which spans the Charles River between Boston and Cambridge and connects to the Comm. Ave. Bridge? That is also closed to cars, but open to pedestrians and bicycles, right?

Seay: That's the difference this year. The BU Bridge was open last year, but because of the section of the Comm. Ave. Bridge they’re replacing, the BU Bridge is closed. Bicyclists are a little disappointed; they thought they could ride their bikes over the bridge this morning. But they found they had to get off, dismount, and walk over with all the other pedestrians. They’re a little upset about that, but they said they'll get used to it and they'll find their way around.

Also, there are many, many road detours in place. Lots of roads connecting to Comm. Ave., all the way from you know the site of the Comm. Ave. Bridge down to Blanford Street, Babcock Street - all of those streets are now closed, so people who aren't aware of what's going on are going to find themselves a bit perplexed by some of the detours. Plenty of signs, and I must, say plenty of people there to help guide them.

LeMoult: Those roads are all closed down for the next two weeks?

Seay: Yes.

LeMoult: Wow. Did you see a lot of traffic out there this morning?

Seay: There are a lot of people who obviously came up to those road closure signs, they look one way or another. Police were there to help them. Some people insisting that they had to drive the wrong way down one-way streets. It was a little frustrating for them. but the police tell me they expected this. They're trying to help people out, and for the most part, people are cooperating.

LeMoult: And you went to a MassDOT press event this morning, with officials there. What did they have to say?

Seay: Well, they say things did go smoothly this morning. There was no disruption of traffic on the Mass Pike, but they warn that lane restrictions are not going into effect until 9 o'clock tonight. And those restrictions will be significant.

We're talking about eight lanes of traffic being reduced to three lanes of traffic at nine o'clock tonight, remaining that way for pretty much the whole duration of this project. People are going to have to get used to the fact that traffic may be backed up much worse than usual. And of course we know the Mass Pike isn't ideal to begin with. So if there's any way you can avoid this area over the next two weeks, that's what officials are advising you to do.

LeMoult: Sounds like Monday morning, that's when we're really going to see some serious mess.

Seay: Yes, and they are hoping because last year went so smoothly, they're hoping that people don't say, 'hey, you know, last year wasn't that bad, I think I’ll try to drive in.' Because if too many people do that, then it really is going to be as they call it the "Pike-ocalypse.”

LeMoult: As a commuter, two weeks might seem like an awfully long time for this to happen, but on the other side of it, it's kind of amazing they're actually going to get it done in two weeks.

Seay: They told me that it would be three to five years using traditional methods, so this is a very aggressive construction effort. And even though it is going to be disruptive for two weeks, it could have been a lot worse.

LeMoult: Thanks, Bob. That's WGBH Radio's Bob Seay, who has been covering construction on the Commonwealth Avenue Bridge. The bridge is closed to traffic for the next two weeks as it undergoes repairs. This is All Things Considered.