The Montgomery County Council is poised to take a key vote Tuesday on a measure that could dramatically urbanize parts of the county and guide the jurisdiction’s development for years.

The plan would help create a string of small, walkable cities in traditionally suburban areas where the county wants mass transit. Supporters say it could usher in a new era of more coordinated growth.

But opponents say the plan does not include enough checks on development and could lead to overcrowded roads and neighborhoods, as well as high-rise complexes that would overshadow traditional single-family neighborhoods.

The debate over the proposal started soon after planning officials began working on it more than a year ago. And the debate adds to the pressure the council is feeling as the vote approaches.

Commercial development “is critically important,” said the county’s planning director, Rollin Stanley. “We don’t have many places left to grow, and that’s the last frontier for us.”

The planning staff is rewriting the regulations that underpin county development. They say that the rules are convoluted, ineffective or both. With the new proposal, they hope to replace much of the regulations guiding commercial development.

There is pressure on the council for quick approval. Planning officials have proposed development plans assuming that a version of the measure will be approved. Stanley said a delay in the vote would derail current and future plans in Wheaton, Takoma Park, Kensington and other areas of the county and would push back the rewrite and frustrate residents and developers alike.

The council has another motivation as well: Montgomery has undergone a sea change in development. The catch phrase five to 10 years ago was “slow growth,” and county officials were tougher on developers — they could be, because of growing budgets and the stable economy.

Now the catch phrase is “smart growth,” and some county officials are unsure whether it appeals enough to developers. Though council members say they need to strike a balance among the interests of community stakeholders, they also make it clear that the county — confronting stark fiscal realities — needs to do a better job attracting developers and stimulating the economy.

“Quite frankly, we said we needed to make it easier for these people to build in these communities,” Council Vice President Roger Berliner (D-Potomac-Bethesda) said at a council meeting last Tuesday.

Still, the public will benefit, planning officials say, because the plan would dramatically increase public input in commercial development. Critics say there still isn’t enough public participation in the new regulations, especially those that govern development next to single-family housing.

The measure itself is so complex that some county employees have given up learning it, and others have spent hours in meetings trying to grasp the basics. The council is also considering multiple versions, each with its own sets of restrictions and incentives.

Ten council meetings have been devoted to the details, including incentives for building public amenities such as libraries and affordable housing. Some versions anger civic associations, who want greater restrictions to protect their interests, and others frustrate developers, who want greater flexibility to protect theirs.

Some council members, such as Marc Elrich (D-At Large), say they want their colleagues to address more community concerns.

“Accurately anticipating the impacts of changes [like this proposal] is both critical and challenging,” said council member Phil Andrews (D-Gaithersburg-Rockville). “My concern . . . is not about the concept but about whether the crucial details are sound.”

The lack of consensus over what will work in “the best interests of the county” has made County Executive Isiah Leggett (D) skittish.

“The whole thing is tantamount to a disaster waiting to happen,” he said.

Nonetheless, council member Nancy Floreen (D-At Large) said she expects that her colleagues will finalize details on the proposal and take a straw vote Tuesday.

“The horse has left the barn with this one,” she said.