Gov. Charlie Baker told Boston Public Radio on Thursday that his administration stands by his public transportation investment plans, even as he faces criticism for not going far enough to address traffic congestion.

The Boston metropolitan region has 300,000 more cars and trucks than it did five years ago, according to an analysis of state data done by The Boston Globe.

Baker said Thursday the state has also added 300,000 jobs to the economy over the past five or six years, which strains a "public transportation system that hasn't been invested in forever."

"We are absolutely paying catch up across the board on this stuff," he said. "That's why we took such an aggressive position on investing in our public transportation system."

Baker has proposed an $18 billion bond bill to fund public transit investments, which would be used to fund existing programs and several new initiatives aimed toward sustainability over the next 10 years, according to a press releasefrom his office.

"It's important to understand that the big issue at the T right now is about how fast we can move the resources to get the work done and still run the line every single day. … The idea that the state isn’t making a big investment in people who ride public transit just isn’t true," he said.

Transportation advocates say modernizing the MBTA may be more to the tune of $50 billion, as a new report by transportation coalition A Better City calls for.

Baker also responded to the fascination withhis own public transit ridership as governor.

"I talk to people all the time who ride the public transit system. I'm not a virtue signaler," he said. "My job is to try to make the thing better, and given what we inherited on that thing, I'll put our record up against any of our predecessors."

Correction: A previous version of this story incorrectly named the transportation coalition that wrote the report "Funding Transportation Solutions." That coalition is called A Better City.

During his monthly Ask The Governor segment with Boston Public Radio, Baker also discussed the education, flavored nicotine product ban, and hands-free driving bills sent to his desk; transparency at the RMV; and the new head of State Police.