The state highway department is spending nearly a half-million dollars and nine months to improve lighting at the interchange of Interstate 10 and La. 22 on the southern edge of Ascension Parish.

The department is removing existing lights and replacing them with “high mast lights” and also putting in new lights under the I-10 overpass bridges crossing La. 22 in Sorrento, Dustin Annison, spokesman for the state Department of Transportation and Development, said Friday.

“The project will help to improve safety and visibility at this interchange,” Annison said.

He said work began in March and “is scheduled to finish by the end of 2014.”

The six, high-mast light poles are planned to be 100 feet tall and each have eight 1,000-watt, high-pressure sodium lamps, or luminaires, at the top, DOTD plans say. High-pressure sodium lamps typically give off an orange-yellowish light.

The new lights under the overpasses will also be high-pressure sodium lamps but at a lower wattage, DOTD plans say.

The project is expected to cost $492,398, which is about $102,000 under the estimated construction cost, according to bid documents. The apparent low bidder in a May 15 letting was Jack B. Harper Electrical LLC of Walker, the DOTD website says.

Rolling roadblocks on I-10 east and westbound between La. 44 and U.S. 61 are scheduled from 7 a.m. and 5:30 p.m. Wednesday to Friday and June 2 to June 6.

The I-10 eastbound and westbound inside shoulders also will be closed at the La. 22 exit, Annison said.

He said the roadblocks are needed to allow the contractor to transport equipment and materials to the median of I-10 safely.