The strength of Los Angeles County’s commercial real estate market helped soften the blow of the credit crunch in the third quarter, even as the region’s exposure to the subprime lending crisis took its toll on some submarkets.

Brokers report that sales are taking longer to close and developers were pausing before pulling the trigger on new construction. Office vacancies in the west and central portion of the San Fernando Valley soared as mortgage lender Countrywide Financial Corp. and other related residential real estate businesses gave back space or even closed shop.

“In our marketplace there is always a dynamic between greed and fear,” said Bob Scullin, chief executive for Southern California of NAI Global. “Right now, fear is driving the market.”

Demands of security-minded bankers are driving much of the slowdown. Lenders want to see healthy current cash flow before they’ll finance a sale, rather than bank on projections of how much a new owner will be able to jack up rents.

“For buildings with stable cash flow and several long-term leases, there’s still money out there at competitive interest rates to get those deals done,” said John Anthony, senior managing director for the greater Los Angeles office of Charles Dunn.

Less access to leverage also is reducing the number of bidders for properties, according to Chris Cooper, senior managing director for the Los Angeles office of Cushman and Wakefield.

“What you are seeing is that instead of 20 bidders coming to the table, you might see just eight or nine,” Cooper said. “Plus, you’re less inclined to kick your No. 2 or 3 bidders to the curb once you sign a contract, because things can happen to No. 1.”

The countywide office vacancy rate dropped to 9.2 percent, compared with 9.6 percent in the previous quarter and 9.7 percent a year ago, according to Grubb & Ellis Co. Even more striking: Class A asking rents are up 17 percent from a year ago, and even Class B rates have risen 12 percent for businesses priced out of higher quality buildings.

In a more robust funding market, those trends would have developers moving ahead with new projects. “The demand is clearly there, our business volume is picking up, but not until the credit crunch gets straightened out and funds become available will developers start to become actively involved again,” said NAI’s Scullin.

Even so, business at Scullin’s office is up 17 percent year-to-date. “What that signifies to me is that while deals are taking longer to get done, they are still closing because the demand is so high and supply is so low,” he said.

Even as most submarkets are experiencing single-digit vacancy rates and historically high asking rents Burbank has the county’s lowest vacancy rate at 3.4 percent, led by its desirable Media District the San Fernando Valley as a whole was a notable drag on the overall county statistics.

Vacancies in the Valley rose to 7.8 percent from 6 percent, with the western reaches leading the pack at 10.3 percent as the market gave back space. (The change was due to the concentration of mortgage businesses in the area.) Even so, Class A asking rents throughout the Valley continued to rise, up 5.5 percent to $2.85.

Elsewhere in the county, Class A rents in Westwood, where vacancies fell to 6.6 percent, shot up 24 percent to $5.60 between the second and third quarters. Beverly Hills, Brentwood and Century City also hit milestones, with asking rents passing the $4 mark in each area.

“The level of interest, the number of tenants in the market is much stronger than it was even one, two or three quarters ago,” said Anthony at Charles Dunn. “Tenants are coming in a year early to renew because they see where rents are going.”

Century City, the largest Westside submarket, saw its vacancy rate head back down to 9.3 percent after a second quarter upward blip following the opening of 2000 Avenue of the Stars. Even as some longtime tenants are opting for cheaper rents in the now trendy downtown, businesses that need to stay on the Westside are taking their place.

As the quarter ended, two asset management firms, Canyon Partners LLC and Ares Management LLC, each leased an entire floor at 2000 Avenue of the Stars. In the case of Ares, the firm is moving from smaller offices across the street. Neither deal is reflected the third quarter numbers.

“Century City is definitely the most dynamic place on the Westside right now, and that’s because of the large blocks of space now available,” said Stan Gerlach, senior vice president at the Beverly Hills office of CB Richard Ellis. “If you’re a 100,000-square-foot tenant who wants to be on the Westside right now, 2000 Avenue of the Stars is one of the few options you have.”