BOSTON -- A major milestone marking the beginning of the end of the Big Dig is set to open this weekend.

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Officials Show Off New Tunnel See A Map Of The New Tunnel (PDF)

The Interstate 90 connection to the Ted Williams Tunnel will open sometime over the Martin Luther King Jr. Day weekend. Motorists will be able to drive to Logan International Airport directly from the Massachusetts Turnpike.

A ceremony will be held Friday to mark the tunnel's completion, but it won't be open until later in the weekend. Officials said that they don't want to give out the actual time because they don't want drivers attempting to be the first one through the new tunnel.

The tunnel was delayed from its planned December opening because of problems with the "smart" technology that monitors the tunnel for traffic accidents and other problems. After a successful test of the technology, officials recently announced the revised opening date.

Drivers will now have new options for getting to the airport:

From the west: Motorists can simply stay on the Massachusetts Turnpike, which will connect directly to the Ted Williams Tunnel, which will be open to all traffic as soon as the new tunnel opens.

From the north: Drivers coming from the north on I-93 South will still take the Callahan Tunnel, even after the Big Dig is completed. The idea is to split traffic between the tunnels to make the ride easier.

From the south: The Callahan Tunnel will also be the main way to get to the airport for the time being, so take I-93 North to the tunnel. A new exit 20 ramp connecting I-93 North to the eastbound turnpike and the Ted Williams Tunnel is scheduled to open around Jan. 25. That should then be the quickest way to get to Logan.

Leaving the airport will also be a bit different:

Going west: Use the Ted Williams Tunnel to connect directly to the turnpike.

Going north: Drivers will have the same route for now. Take the Sumner Tunnel to I-93 North. When the new northbound lanes of the Central Artery open in about a month, a new ramp will connect the turnpike to I-93 North, making the Ted Williams Tunnel the best option.

Going south: Continue using the Sumner Tunnel. There will eventually be a ramp connecting the westbound Turnpike to I-93 South.