Construction is underway to add carpool lanes to the Loop 202 Santan Freeway in Chandler, which will trigger some weekend freeway closures until the project is completed in early 2012.
But traffic should flow smoothly during most of the project because the freeway will remain at three lanes in each direction, said Laura Douglas, a spokeswoman for the Arizona Department of Transportation.
"Most of the work will be done during the overnight hours and the weekend, so it won't be an impact on the daily commute during the weekdays," Douglas said.
The project will add 12 miles of carpool lanes, from Interstate 10 to Gilbert Road.
Initially, work will take place from the Loop 101 to Gilbert. ADOT hasn't established a start date on the remaining section.
The work will require a closure this weekend. The westbound lanes will shut down from Gilbert Road to the Loop 101 as work crews install concrete barriers to separate the median from traffic. The project also involves shifting the lanes slightly.
ADOT hopes the lanes make carpooling more attractive, as the lanes will connect with existing carpool lanes on I-10 and the Loop 101.
ADOT has built 50 miles of carpool lanes since 2008.
The carpool lanes are restricted from 6 a.m. to 9 a.m., and from 3 p.m. to 7 p.m. on weekdays.
During those times, the lanes are open only to passengers with two or more people, along with motorcycles, alternative-fuel vehicles and buses.