The first phase of the revamp of the Highway 99/120 connector and the nearby Austin Road interchange will take place in six stages over two years starting next month.

It will periodically involve several significant detours.

The six stages of the first phase construction being overseen by the San Joaquin Council of Governments are as follows:

First stage

It will include initial work on adding a second connector lane from the 120 Bypass eastbound to Highway 99 southbound.

That work will require the 120 Bypass eastbound to be closed several nights between 11 p.m. and 5 a.m. with traffic detoured off at Main Street to Moffat Boulevard.

The first stage, which will cover four to five months, includes constructing a new roadway between Austin Road and Atheron Drive as well as widening Woodward Avenue east of Atherton Drive to Moffat.

Local traffic will remain on existing roadways.

Second stage

Then in the next one to two months, major construction will start on the connector ramp.

The daytime construction will not require any freeway closures.

At the same time, the Austin Road overcrossing is removed to temporarily eliminate the ability to cross Highway 99 using Austin Road.

The at-grade railroad crossings on Austin Road and Woodward Avenue will remain open.

Freeway ramps will remain open.

Third stage

The third stage will span one to two months.

Woodward Avenue will be closed to widen it to four lanes from Atherton Drive to Moffat Boulevard with new railroad crossing gates. It will be similar to the configuration of Industrial Park Drive where it crosses the tracks to intersect with Moffat.

Local traffic will be detoured to Austin Road via the new connecting road built in the first phase between Austin Road and Artherton Drive.

Fourth stage

Woodward Avenue widened to four lanes will open during the next stage that will take between open to three months to complete.

Austin Road sill be closed between Singh Street (the new name of the connector street built in the first stage) and Moffat Boulevard.

Highway 99 freeway lane widening will start. Existing freeway lanes will be reduced between 11 p.m. and 5 a.m.

The southbound exit from Highway 99 to Moffat will be closed intermittently.

The northbound Highway 99 entrance ramp from Austin Road will remain open.

Fifth stage

This is when the new Austin Road overcrossing bridging both Highway 99 and the Union Pacific railroad tracks will be built.

Sixth stage

The final stage will take between 1 to 2 months.

The Austin Road ramps on the northside of the interchange will be permanently closed.

The northbound off-ramp to Austin Road will be closed for a week for new construction.

Austin Road will be widened to four lanes from the interchange to the Frontage Road will some improvements made to the Frontage Road.

Final construction will be completed on the second connector lane.

To contact Dennis Wyatt, email dwyatt@mantecabulletin.com