There is a huge difference between overpopulation and building your society around everyone being in a single occupancy motor vehicle to go anywhere or do anything.

The densest counties in MD average around 2k per sq km. By comparison Manhattan has a density of 30k per sq km. We are not "overpopulated". We simply have not built to support having any degree of population density.

As more people move to a place, you have to start planning around incentivizing people to live denser and get around without a single occupancy vehicle. Relative to our densities, we have anemic public transit and bike infrastructure, and almost all of the state is zoned for exclusively single family residential housing.

This is a problem we built for ourselves and was in no way inevitable. Some immediate big ticket things we can do are widen the Camden line and get high frequency electrified train service on it between Union and Camden station, rezoning all around its stations for high density urbanism. We can also rezone around every existing metro station in DC and around all the MARC stations and existing MTA subway / light rail in Baltimore for density, giving people places to live where they can get around without driving.

I think a lot of the problem ultimately is Baltimore's depopulation. Baltimores design would support up to 5 million people living in its urban fabric if its fixed rail lines were rebuilt and it had adequate bike infrastructure put in place and i83 was decomissioned. But due to corruption, white flight, racism, systemic disinvestment from the state, and again 50 years of extremely corrupt governance the city is a hollowed out husk of what it should be.

If the surubanite car owner wants to continue to perpetuate their lifestyle of living with a big yard while driving everywhere from their homogeneously zoned R1 neighborhood it is in their self interest to pressure the state into rebuilding Baltimore and building a comprehensive first class rail network to let people who are willing to live in denser, walkable neighborhoods to do so. If that happened, all the old guard residents would have all the space on their suburban stroads and freeways they want.