Residents along Contra Costa Co. highways will hear gunfire tonight for ShotSpotter equipment tests

People living along highways in Contra Costa County may hear gunfire tonight when the California Highway Patrol shuts the roadway down to test equipment for a ShotSpotter gunshot detection system.

"It's going to be a combination of live fire and blanks," Capt. Dan Seaman, commander of the CHP's Contra Costa-area office, said today during a news conference in Martinez.

Seaman said there have been 136 shootings reported on highways in the nine-county Bay Area since the CHP first started tracking them in November 2015, with 44 of them in Contra Costa County on state Highway 4, state Highway 24, state Highway 160 and Interstate Highway 80.

In some cases, the ensuing investigations have closed the affected roadways for hours as officers search the scene for evidence, like spent casings or other indicators of gunfire.

Testing is scheduled to begin at 9 p.m. and continue until 4 a.m. Friday, a timeframe selected to minimize impacts on traffic and avoid inconveniencing commuters.

The CHP has declined to provide specific locations for where that testing will occur, but they warned that intermittent lane and road closures should be anticipated.

Once the equipment is installed and fully functional, it should help law enforcement pinpoint the time and location of any shootings that occur on area highways.

The next step is going to involve installing cameras and automated license plate readers to help identify suspect vehicles in shootings. That phase of the project is expected to be completed by the end of this year.