NORTH SALT LAKE — Community leaders from along the Wasatch Front unanimously approved a five-year Transportation Improvement Plan despite concerns voiced by local environmental groups that the plan would create more traffic and worsen air quality.

Representatives for the Sierra Club and Utahns for Better Transportation pleaded with leaders at a Wasatch Front Regional Council meeting Thursday to reject the plan, which they say violates federal clean-air standards. Sierra Club members also criticized the 20-year transportation plan, which they say banks on future availability of light rail and cleaner vehicles.

Sierra Club spokeswoman Nina Dougherty argued that environmental impacts need to be considered "not just 20 years from now but in the next few years."

Dougherty also criticized the proposed Legacy Parkway and the mentality that building more roads will alleviate traffic when it really promotes urban sprawl and increases commuting, she said. Sierra Club members have also been critical of the planning process, which they say has not involved enough public participation and open meetings.

In November, the group sent the regional council a 59-page letter with additional attachments detailing its concerns about a lack of open meetings and published materials and what it said were faulty pollution models used to determine the amount of pollution that would be created by traffic on Legacy Parkway.

Brigham Daniels of Utahns for Better Transportation told the council that the models met federal air-quality standards because only cars traveling at average speeds were taken into consideration. He said those models were inaccurate because vehicles produce more pollution when traveling at low or high speeds.

Council member Mick Crandall defended transportation and pollution models as well as the level of public participation and notice involved in approving the transportation plan.

"The long-range plan conforms to air-quality standards," he assured the council.