Lane shifts are under way for eastbound motorists as part of the widening work on Interstate 10, officials said Wednesday.

The changes mean that:

• Starting Wednesday night, eastbound motorists traveling between the I-10/12 split and Essen Lane were moved to the newly constructed inside lane of the interstate.

• Starting Saturday night, eastbound motorists will move to the new inside lane between Picardy Avenue and east of Siegen Lane.

The changes will be in effect for about one year, officials of the state Department of Transportation and Development said. About 115,000 motorists use that 4.1 mile corridor daily, said Jodi Conachen, communications director for the DOTD.

The new traffic patterns are part of two projects that will add one lane in each direction from the split to Highland Road. The $86 million project between the split and Siegen Lane began in January 2009.

It was originally supposed to be finished by the end of this year. But DOTD officials announced in May that the work is 10 months behind schedule and is now set for completion in fall 2012.

The $60 million project to widen I-10 from Siegen Lane to Highland Road is set for completion in late 2012.

The two lane shifts will also require other temporary traffic disruptions.

They are:

• Alternating I-10 eastbound lane closures between Bluebonnet Boulevard and the Ward’s Creek Bridge east of Siegen Lane on Saturday at 8 p.m. until Monday at 5 a.m.

• Closure of the Picardy Avenue on-ramp to I-10 eastbound from Saturday at 8 p.m. until Monday at 5 a.m.

• Closure of the Siegen Lane on-ramp to I-10 eastbound from Saturday at 8 p.m. until Monday at 5 a.m.

In July the work required lane shifts for westbound motorists.

Drivers between Bluebonnet Boulevard and the split were moved toward the median lane, also for one year.

In addition, the entrance ramp to westbound I-10 at Picardy Avenue will be closed for one year while the lane shifts are in place.

The I-10 work is part of a series of projects that includes the addition of one lane in each direction from the O’Neal Lane interchange to Juban Road.

A new bridge is also being constructed over the Amite River.

All the work will cost an estimated $332 million and is set to be done by 2013.