Gov. Larry Hogan announced late last month that the state will spend millions to ease congestion on portions of the Baltimore Beltway that bisect some Catonsville and Arbutus neighborhoods.

The plan would convert 19 miles of the interior shoulders in both directions on Interstate 695 into new travel lanes between I-70 and Parkville, a move state officials said would cut about 15 minutes off rush hour delays that can stretch an hour or more.

Hogan’s plan would rebuild the aging interchange at I-70 and I-695 north of Catonsville to mitigate a daily bottleneck there and also nearly double the length of the northbound express toll ways on I-95 — extending them from White Marsh to Route 24 in Bel Air.

Commuters would see stoplights at on-ramps to help manage traffic flow. Five bridges would be rebuilt, and four new sound walls would be installed.

Construction would begin no earlier than late summer 2018, state officials said.

Hogan, who announced the $461 million plan at State Highway Administration headquarters in Hanover, described it as part of an ongoing effort to improve the state’s road infrastructure.

He said the Baltimore plan “will benefit the daily lives of millions of drivers throughout the Baltimore region.”

Some commuters celebrated the announcement as long-overdue.

“Yay, this is awesome,” said Ragina Cooper-Averella, spokeswoman of AAA-Mid-Atlantic.

But some transportation advocates questioned whether widening the Beltway would solve congestion long-term or merely invite more motorists to start using the roadway.

“We’re questioning the wisdom,” said Brian O’Malley, president and CEO of the Central Maryland Transportation Alliance.

O’Malley emphasized that his group is “agnostic” about which mode of transportation is best, but added there’s little evidence across the country that additional traffic lanes reduce gridlock for long.

“No one has been able to build their way out of their congestion,” he said.

The Baltimore plan adds to the Republican governor’s ambitious proposals to widen the state’s highways to cut down on traffic congestion.

Last year, Hogan announced a $9 billion idea to install express toll lanes on the Capital Beltway through the Washington suburbs and to widen the Baltimore-Washington Parkway after taking ownership of it from the federal government.

Reaction to the governor’s broader strategy has been mixed, with some motorists cheering the prospect of faster-moving highways and transit advocates frustrated with huge investments in roads at the expense of other transportation options.

Baltimore County Executive Kevin Kamenetz, who is running in the Democratic primary to challenge Hogan, said in a statement that “widening the Beltway is a piece of the plan, but unless we invest in a real mass-transit solution we’ll be stuck in traffic for years to come.”

The Baltimore plan announced before Christmas does not require legislative approval.

The costliest piece of the plan extends the I-95 express toll lanes by 7.75 miles. That $210 million project will be overseen by the Maryland Transportation Authority, whose projects are generally paid for with money from tollways.

The lanes, which run between White Marsh and I-895, cost drivers who use them as much as $1.54 each way in rush hour traffic.

The new travel lanes on the Beltway will cost $151 million, and the new interchange at I-70 and I-695 will cost $100 million to design and construct. Both of those will be overseen by the Maryland Department of Transportation, whose projects are generally paid for with money from the state’s Transportation Trust Fund.

The governor, a Republican, campaigned in 2014 against the gas tax increase that is now being used to finance road projects across the state. In his first year in office, he attempted to roll back part of that increase.

In addition to criticizing Hogan’s highway-building plans, transit advocates continue to lambaste his 2015 decision to cancel the proposed $2.9 billion Red Line light rail project in Baltimore, which he called a “boondoggle.”