Update 7:48 p.m. Sept 5
CHP Officer Kenyon Youngstrom has reportedly been pronounced dead.
Update 11:29 a.m. Sept. 5
Update 4:14 a.m. Sept. 5
I-680 is open. The San Jose Mercury-News has more details on the shooting that shut down the highway on Tuesday, including the name and condition of the CHP officer:
Officer Kenyon Youngstrom was shot through the neck after pulling over a Jeep Wrangler on the shoulder of the freeway, police said. Moments later, a second CHP officer who had pulled up behind the jeep shot the man in his vehicle and aided the injured officer until emergency medical crews arrived, said Contra Costa sheriff's spokesman Jimmy Lee.
Youngstrom, a 37-year-old married father of four, was taken to John Muir Medical Center and was listed in critical condition as of Tuesday night with what KGO-TV described as a severed spinal cord.
Flowers were placed outside the two-story home of the officer in Cordelia, near Fairfield, as CHP colleagues came by to support the family. A man who answered the door at his home declined to be interviewed.
The officer's family "asked for everyone's prayers as Officer Youngstrom fights for his life," Paul Fontana, assistant chief of the CHP, said in a brief statement Tuesday night.
Youngstrom graduated from the academy in 2005 and worked mostly in the Martinez regional office, having been assigned to the Contra Costa office immediately after graduation. Before joining the CHP, Youngstrom served in the U.S. Army Reserve, Fontana said.
The assailant, who later died at the same hospital, was not identified, pending family notification.
Update 8:44 p.m.
(Bay City News) An officer-involved shooting around 8:30 a.m. on southbound I-680, just north of the Livorna Road exit, initially prompted the closure of the entire highway on Tuesday.
A sheriff's spokesman said a driver shot a CHP officer during a traffic stop, and that a second CHP officer opened fire on the driver.
Both the wounded officer and the suspect were taken to John Muir Medical Center in Walnut Creek, where the suspect died.
Update 1:11 p.m.
NBC Bay Area has Tweeted that northbound I-680 is open.
Update 12:18 p.m.
The Contra Costa Times reports on the alternate route drivers should use to get to 580:
Motorists should use San Ramon Valley Boulevard and Crow Canyon Road from San Ramon to Castro Valley to access east and west Interstate 580. Highway 24 remains open and Caltrans will decide later Tuesday if both tunnels will remain open for the Tuesday evening commute. Expect delays on Highway 13, Interstate 80 and Interstate 880 though out the day and into the evening.
Update 12:04 p.m.
Here is video of the latest CHP briefing of the media, from ABC 7:
Update 11:35 a.m.
From NBC Bay Area, live video of the scene:
Joseph Narvaez Tweeted this photo of traffic being turned around on I-680 in Contra Costa County by CHP.
NBC Bay Area also has this update:
Initially, the CHP said there was no threat to the public, but then later asked for the public's help looking for a black Nissan Maxima, California license plate # 5TZB244 "possibly involved in the officer shooting on I-680 in Contra Costa County."
NBC Bay Area reported that the Nissan was located about 10 minutes after the CHP issued the public alert.
Update 11:04 a.m.
The San Jose Mercury-News is reporting a few details about the shooting that led to the closure:
The (CHP) officer, who has not been identified, exchanged gunfire with a suspect about 8:20 a.m. near the Livorna Road offramp, officials said. Both were rushed to John Muir Medical Center in Walnut Creek with critical injuries.
The officer had made a traffic stop on southbound I-680, just north of Livorna, when gunshots were exchanged for unknown reasons, according to CHP officer John Fransen.
A second vehicle may have been involved in the incident, but no details were released, Fransen told media gathered at the Rudgear Road park-and-ride lot off I-680. There doesn't appear to be any threat to the public, he said.
And from KCBS on Twitter:
Update 10:03 a.m.
— SueHallTraffic (@SueHallTraffic) September 4, 2012
Update: Bay Area News Group is reporting "Southbound Interstate 680 from Livorna Road to South Main Street will remain closed until approximately 3 p.m. due to the active investigation, a CHP dispatcher said."
From a KTVU reporter...
Here's the Google traffic map.