Turning Pecos Road into the proposed South Mountain Freeway could mean less traffic on Chandler Boulevard, Phoenix engineers said this week.

Members of the Ahwatukee Foothills Village Planning Committee disputed those findings at their meeting Monday night, however, saying that the traffic numbers didn't seem to match up with Ahwatukee's population estimates.

Don Herp of the Phoenix Street Transportation Department said the freeway could result in more cars on streets connecting Chandler Boulevard and the freeway.

Herp presented an analysis of Ahwatukee traffic in the year 2030 based on population estimates supplied by the Maricopa Association of Governments.

MAG estimates Ahwatukee's population will be at about 90,000 by 2030. Estimates from the Ahwatukee Foothills Chamber of Commerce peg the current Ahwatukee population at 87,000.

Committee members disputed the traffic numbers, saying that the growth in car trips seemed to outpace the population.

"This is fatally flawed. It's not even close," member Max Masel said of the traffic report.

The proposed 22- to 26-mile highway would connect to Interstate 10 in the west and east, bypassing downtown Phoenix. It would cost at least $1 billion to build. The Arizona Department of Transportation has proposed connecting the eastern leg along Pecos Road.

If the South Mountain Freeway were built, traffic could decrease by as much as 10,000 car trips per weekday on certain sections of Chandler Boulevard, compared with a no-build situation, according to the report.

"Even if you take away Pecos Road as a local arterial street, it doesn't overload or cause any significant traffic problems on Chandler Boulevard," Herp said.

Traffic on streets that would serve as exits for the freeway, such as Desert Foothills Parkway, 24th Street and 40th Street, would increase by thousands of trips per day, he said.

One Ahwatukee resident in attendance spoke out against the freeway.

"There is no resource given to validate any of the figures that you people have been given," Greta Rogers told the committee. "If (the freeway) is a wise use of funds, then I'm a monkey's uncle."

The committee decided to wait to take an official position until its April 24 meeting when ADOT representatives will discuss response to the freeway gathered at a November public meeting.