Washington-area developers have begun planning more construction projects than at any time in the past four years, an early signal that the region's struggling economy may finally be rebounding.

Officials in Virginia, Maryland and the District have seen a surge mostly in residential or mixed-use developments, and requests for building permits have reached the point that at least one, Fairfax County, can barely keep up with demand.

Fairfax, which handled 99 major plan reviews last year, expects nearly 120 this year -- the most the county has seen in five years. The surge is swamping a pared-down county staff, who need an average of 92 days to review building plans that were usually done within 60 days.

Building permits in high demand
2012 2011 2010 2009
Arlington* 10 3 3 6
Fairfax 59,971 54,138 52,450 47,268
D.C.* 46^ 57 52 86
MontCo N/A 6,162 5,924 5,571
PG 27,430 25,151 24,658 27,350
*Major projects only ^Through August

"The development community and our staff have been saying they're stretched and that review times are increasing," said Supervisor John Cook, R-Braddock. "We've reached a point now where we need to deal with this."

Fairfax officials have been working to revitalize Reston and redevelop Tysons Corner to promote growth along Metro's new Silver Line, expected to open later this year. Plans for Tysons, which the county hopes to transform from a midsize office park into a new urban downtown, helped jump-start the spike in building permit applications, officials said.

Arlington County officials approved 10 major projects last year, more than triple the number of projects they handled in 2011 and 2010. Numbers were not immediately available for Alexandria.

"The economy is certainly helping construction," said Maggie Parker, spokeswoman for developer Comstock Partners. "There's an awful lot of action right now. It's all a sign of an improved economy, more confidence and more folks coming back into the homes market."

The surge has continued through the first part of 2013, with area developers signing contracts worth more than $1.4 billion, up from $1.2 billion last year, McGraw-Hill Construction data show.

Unlike many of its neighbors, Montgomery County has seen requests for building permits rise each year, from 4,933 in 2008 to 6,162 last year. Prince George's County issued 27,430 permits last year, up from 24,658 in 2010 and 25,151 in 2011.

The District's plans to develop CityCenterDC, a 10-acre site with apartments, offices and shops near New York Avenue, helped fuel the surge in construction. District officials didn't have numbers from last year, but the city approved 52 projects in 2010 and 57 in 2011.

"The Marriott Marquis, City Center, St. Elizabeths and Walter Reed are projects of significant size that you're going to be strained to find outside of D.C.," said Pedro Ribeiro, a spokesman for D.C. Mayor Vincent Gray. "You can make the example of Tysons Corner, but beyond that, what is there? There's very little."

Delta Associates CEO Greg Leisch expects the housing market to continue growing over the next couple of years, a trend that could make up for a lagging commercial real estate market.

"The marketplace typically has a seven-year memory," Leish said. "People now believe in the housing market again. But real estate moves in cycles, so the immediate question is, 'How long will this continue?' "