WALNUT CREEK -- In 2009, an out-of-town rival mall company went toe-to-toe with Broadway Plaza's owner in an attempt to block a Neiman Marcus store from coming to downtown.

Lawsuits were filed, paid signature-gatherers invaded town and, ultimately, Walnut Creek voters made the final call to allow the 92,000-square-foot store to be built.

Four years later, plans for a 300,000-square-foot expansion at the outdoor mall -- as well as major renovations and improvements throughout the center -- have generated far less uproar. In fact, at the Planning Commission's final public hearing on Broadway Plaza's Long Range Master Plan last month, no one offered public comment.

Mayor Kristina Lawson said she thinks that's because residents are committed to downtown Walnut Creek.

"In 2009, our own residents overwhelmingly confirmed their commitment to a thriving downtown after out-of-town interests tried to throw Walnut Creek off course," she said. "Just four years later, it appears those out-of-town interests got the message."

At a special meeting Tuesday night, the City Council is expected to decide on a plan that lays out development at the center for as long as the next 20 years. As part of the deal, the city will enter into a development agreement with Broadway Plaza owner Macerich that would give the company 20 years to implement the long-range master plan, in exchange for up to $5 million in payments to the city.

Earlier versions of the shopping center's long-range plan called for shutting down a public street and even potentially adding housing, but those ideas have been scrapped. Macerich now intends to build more stores, renovate existing buildings, rebuild a parking garage and make myriad other improvements.

The expansion will disrupt businesses at the 60-year-old center, as many store owners will be -- or already have been -- forced to set up shop somewhere else or close down altogether.

The first phase of the plan includes demolishing and rebuilding the parking garage on South Broadway, the expansion of Macy's and the face-lift, remodel or expansion of many other stores. Later plans include construction of a two- or three-story building on the west side of Broadway Plaza, in the current Macy's men's shop location.

Some city officials worry about the loss of parking during construction. Demolition of the Nordstrom garage, which fronts Broadway, will mean a loss of 200 parking spaces for 11 months.

"How are we going to avoid the hell that is going to exist there?" Planning Commissioner Neil Gerstner asked at the November public hearing on the plan.

Garrett Newland, a Macerich vice president, said there is a parking plan that will be implemented during construction.

"It won't be easy, but we will manage it well," he said in November.

Macerich will offer free valet service during peak times, as well as employee shuttles. Plans call for the garage to be ready before the 2014 holiday season.

While most of the expansion will bring more retail similar to that already at Broadway Plaza, there is also room in the plan for two auto dealership showrooms. Extensive landscaping and aesthetic improvements, as well as widening a portion of Newell Avenue to accommodate bike lanes on both sides, is also included.

Besides some pedestrian and bicycle improvements, the addition of left-turn room off South Broadway, and a new signal at Newell and Maria Lane, no other traffic infrastructure improvements are in store. That worries some city planners.

"I really don't understand how we are handling the 300,000 square feet of load ... I don't understand what we are doing to handle the traffic -- because (traffic) is bad now," Planning Commissioner Bob Pickett said at the November meeting.

Macerich officials said the city's general plan environmental impact report does consider this kind of expansion.

Other planners said it's in the mall owner's best interest to not create more traffic problems, as that would discourage shoppers.

Lawson pointed out the expansion's benefits, including the number of local construction jobs it will create.

"The expected quarter-billion dollar investment by publicly traded Macerich Co. is a huge win for Walnut Creek and confirms that Walnut Creek is the place to be in the East Bay," she said. "In the long term, Macerich's significant investment will help ensure Walnut Creek remains a regional leader -- not only from a shopping perspective, but from a quality-of-life perspective, too."

Contact Elisabeth Nardi at 925-952-2617. Follow her at Twitter.com/enardi10.