As plans move forward on how best to tackle growth caused by Metrorail’s extension into Reston, a community ad hoc committee is discussing traffic mitigation.

On Tuesday, Reston Master Plan Special Task Force members heard from county traffic experts on possible options to stem highly congested intersections near the future Wiehle Avenue station. The county plans to revisit zoning in the Reston area in preparation for Metrorail’s arrival at Wiehle in late 2013. The task force is studying predicted residential and commercial density levels in an effort to make a land-use recommendation for the county.

Residential growth alone in the Reston-Dulles corridor is expected to double during the next 50 years, according to a 2010 study by George Mason University. As many as 26,000 new jobs could come to the area by 2050 as a result of Metrorail expansion.

Even with rail’s arrival, Reston likely will see more congestion, county officials said.

“We’re well aware of the fact that there is a big menu for mitigations,” said county Senior Transportation Planner Dan Southworth during Tuesday’s meeting at the Reston Community Center Lake Anne.

Discussion focused on possible improvements to five intersections: Wiehle Avenue and Sunrise Valley Drive; Wiehle Avenue and Sunset Hills Road; Reston Parkway and Sunrise Valley Drive; Reston Parkway and Sunset Hills; and Fairfax County Parkway and Sunrise Valley.

Wiehle Avenue and Sunrise Valley Drive

Possible improvements to the intersection could mean implementing a free westbound right-turn lane on Sunrise Valley to replace the current right-turn lane at the traffic light, which would allow for smoother flow of traffic.

“This could be a good fix here,” Southworth said, adding that the change could bring a 53 percent improvement for morning traffic and a 12 percent improvement for evening traffic.

The difference to the morning wait at this intersection would lower it from an average of 87.2 seconds at the light to 40.9 seconds, he said.

Wiehle Avenue and Sunset Hills Road

Current county plans for the Wiehle Avenue and Sunset Hills Road intersection call for the widening of Sunset Hills Road to six lanes, with free eastbound right turns. The westbound through and right lane at this intersection would become a through-only lane. One of the westbound lanes would be designated as through-left.

Southworth said the changes here were “not major improvements but some significant impact.”

Morning traffic would see a 7 percent improvement, while evening drivers would see a 65 percent improvement at peak hours, he said.

Reston Parkway and Sunrise Valley Drive

Proposed plans include adding a northbound and a southbound through-traffic lane, implementing a free westbound right-turn lane and restriping an eastbound approach to eliminate one of the two left-turn lanes.

This intersection, Southworth said, likely would remain a highly congested one despite the changes.

“All we can do really is make a better ‘F’ [grade intersection], but it’s still a 23 percent improvement [for morning traffic],” he said.

Reston Parkway and Sunset Hills Road

Several possible changes to improve this intersection are being examined, Southworth said, including one that would extend streets across the W&OD Trail, and add eastbound and southbound through lanes. The result could mean a 50 percent improvement for morning traffic, according to the county’s study.

Fairfax County Parkway and Sunrise Valley Drive

“We’ve got a really bad problem at both morning and evening peaks,” Southworth said of this intersection, and the county is considering a wide range of mitigation strategies, including a possible interchange that could mean a 60 percent improvement for morning traffic and an 89 percent improvement for evening traffic. Other possible mitigation strategies for this intersection involve adding southbound, northbound and eastbound through-turn lanes. The result could be less of an improvement than what an interchange could offer, according to staff.

Although task force members will further discuss traffic mitigation at a meeting next Tuesday, several task force members this past Tuesday expressed concerns about the impact the county’s mitigation efforts will have on pedestrians. Task force members said they also were concerned about accessibility to the Dulles Toll Road, which they said could be impeded by the Wiehle Avenue and Sunrise Valley Drive intersection options.

“Given the north-south traffic issues [in this area], I think the long-term solution would be to build a light rail at these intersections,” said Judith Pew, an at-large member, citing the Fairfax County Parkway and Sunrise Valley Drive intersection specifically.

A further discussion of traffic mitigation is scheduled for Tuesday at the North County Government Center. For the complete county traffic mitigation report, visit www.fairfaxcounty.gov/dpz/reston/

hhobbs@fairfaxtimes.com