Drivers traveling on Highway 99 in the construction zone on the Kings River bridge just south of Kingsburg sometimes face tense moments and congested traffic.

The speed limit drops to 55 mph and lanes narrow and shift slightly as construction crews work on widening that stretch of the freeway from two to three lanes in each direction.

But drivers -- at least the ones heading south -- can expect the flow to improve within the next few months, Caltrans spokesman Jose Camarena said. The reconstructed southbound lanes will open this summer, and the northbound lanes are expected to open next spring, he said.

The project began nearly a year ago and is scheduled to be completed in August 2014, Camarena said.

In the meantime, motorists should continue to use caution, be patient and heed signs warning them about the lane shifts and lower posted speed limit of 55 mph, Camarena said. The speed limit approaching the area in both directions is 70 mph.

Safety for drivers and construction workers is the top priority, and some inconvenience is necessary to make the improvements, Camarena said.

"All of this has to happen to keep the highway open," he said.

Fresno resident Andrea Gjerde, who travels through the area about twice a week for business, said many motorists don't pay attention and slow down, creating anxious moments.

"My heart races as I'm going down there," said Gjerde, a pest control adviser.

And the traffic hassles for Highway 99 drivers are about to head north. Drivers can soon expect similar lane shifts and a lower speed limit with the beginning of a project to widen the freeway from two to three lanes in each direction just north of Fresno, including the San Joaquin River bridge, Camarena said.

That project will run from Grantland Avenue in Fresno County to Avenue 7 in Madera County and is not expected to conclude until summer 2016.

Meanwhile, Caltrans is reminding recreational water users to avoid the San Joaquin River near the construction site.

Water users should exit the river at Camp Pashayan, Caltrans said. Anyone using the river within the construction zone may be cited for unsafe trespassing.