The city will be conducting nighttime soil sampling work from East Kapolei to Waipahu beginning next Tuesday as part of the Honolulu Rail Transit Project.

The mayor's office said soil sampling is part of the preliminary design work for the first portion of the rail route running 6.5 miles between East Kapolei and Pearl City. Kiewit Pacific, which was selected to design and construct the first segment of the rail transit route, will conduct the preliminary testing work.

Work in residential areas will be done at night primarily along the Farrington Highway median between Waipahu High School and Fort Weaver Road, the city said. Night work along Farrington Highway will run from May 27 until early September.

"Testing the soil stability along the route will help us refine the design and location of concrete pillars that will support the elevated guideway," said City Department of Transportation Services Director Wayne Y. Yoshioka in a statement

Work will require some nighttime lane and intersection closures Sundays through Fridays between 7 p.m. and 6 a.m. west-bound and 6 p.m. through 5 a.m. east-bound. One lane of traffic in each direction along Farrington Highway will remain open during the night work.

Motorists using Farrington at night are warned of possible traffic delays and advised to take alternative routes during work hours.

For updates on work days and times, check the project website at www.honolulutransit.org or contact the city hotline at 566-2299.