An electronic  message sign for eastbound 120 Bypass traffic approaching Airport Way is the latest effort by Caltrans in a bid to reduce carnage on what has become the deadliest section of freeway in the Northern San Joaquin Valley.

While the sign can be programmed remotely to flash whatever message Caltrans wants, its primary focus is to warn motorists of traffic slowdowns or stopped traffic ahead. There is already an electronic message sign in place closer to Highway 99.

It is roughly three miles from the transition to southbound Highway 99 has that played a major role in accidents over the past seven years that have killed 11 people and injured 815. The CHP expects 2016 to close with 240 overall accidents with about a hundred of those crashes involving injuries. That reflects an accident every 1.5 days that is serious enough to require a CHP response. The bulk of the accidents — and where almost every death occurs — is in the eastbound lanes in the 1.5-mile stretch starting midway between the Union Road and Main Street interchanges and the Highway 99 transition ramps.

The $578,000 project includes tying the new electronic sign into four traffic monitoring installations using cameras to give motorists real time updates on slowing and backed up traffic.

Councilman Richard Silverman noted Caltrans has told him they are looking at lane markings prior to the lane split at Highway 99 that provide an additional visual alert that travel lanes are merging in different directions. Concrete barriers and other suggestions such as plastic traffic pylons advanced by frustrated motorists do not meet approved traffic control device standards as they create other problems. 

The bulk of those accidents are occurring between Main Street and Highway 99 on the eastbound lanes of the 120 Bypass. Most are attributed to people cutting into the right hand lane at almost the last possible minute causing a slowdown and the hitting of brakes.  The Slinky-like effect can go back a mile or more tripping up drivers either following too close or not paying attention.

Manteca Mayor Steve DeBrum Friday said he intends to keep pressure on regional partners and Caltrans to work toward the ultimate solution — an additional transition lane from the 120 Bypass to southbound Highway 99.

That, however, is not as straight-forward as it may seem. The Austin Road interchange overpass built in 1955 poses a major roadblock.

Not only are there off and on ramps in close proximity to the 120 Bypass/99 interchange, but the Austin Road bridge makes it impossible to squeeze in another transition lane with a reasonable merging distance.

There are two alternates are being considered for the long-term improvement.

The first could cost as much as $40 million. It would widen the connector to southbound 99 to two lanes, construct braided ramps (that are physically separated from freeway lanes) at the Austin Road interchange and replace the Austin Road crossing to provide an additional southbound 99 through lane. In some instances braided ramps require constructing bridge structures to send traffic above other lanes.

The second would cost upwards of $29 million and would widen the connector to two lanes, permanently close Austin Road on and off ramps and replace the Austin Road overcrossing to provide an additional southbound 99 through lane.

The long-term project is proposed for funding with help from Measure K sales tax and savings from the Proposition 1B projects for Highway 99 improvements through the Central Valley as well as federal money. 

DeBrum noted the goal the San Joaquin Council of Governments and Caltrans has put in place to tentatively start work in the summer of 2021 is fairly aggressive considering what has to be done.

The installation of series of signs designed to warn drivers as well as changing the striping on the Bypass east of Main Street could start by September 2017. 

The additional signs that will be put in place will be placed on existing overcrossings or sign trusses on eastbound 120 between Interstate 5 and 99. They will read:

u“SR-99 exit 3 miles” at the Airport Way overcrossing.

u“SR-99 North Sacramento, SR-120 Yosemite Sonora” and “SR-99 South Modesto Fresno 2 miles” at the Union Road overcrossing.

u“SR-99 North Sacramento, SR-120 Yosemite Sonora” and “SR-99 South Modesto Fresno 1 mile” at the Main Street overcrossing.

u“SR-99 North Sacramento, SR-120 Yosemite Sonora” and “SR-99 South Modesto Fresno exit only” at the existing sign trusses just prior to Highway 99.

To contact Dennis Wyatt, email dwyatt@mantecabulletin.com