It’s been 56 years since Highway 99 – dubbed the Central Valley’s Main Street – opened as a four-lane freeway through Manteca.Work is starting in November on the $496 million project to widen 13.1 miles of Highway 99 from the Cross-town to the Highway 120 Bypass to six lanes and replace aging interchanges.The initial phase will involve adding a lane in each direction in the median. That work starts in November. Caltrans split the project into phases to take advantage of the fact the actual widening to six lanes did not require a time consuming right-of-way acquisition process.The on and off ramps at Little John Creek near Stockton Metro Airport will be closed with the frontage roads converted into cul-de-sacs.The French Camp Road replacement interchange construction will get underway in March of 2012.