Jackknifed Big Rig Crash Snarls Traffic and Sparks Fuel Spill on Highway 101
A jackknifed big rig caused a major disruption on southbound U.S. Highway 101 near South San Francisco early Thursday, spilling approximately 160 gallons of fuel, closing multiple lanes, and delaying Caltrain service for hours.
Officials report the crash occurred shortly before 5 a.m., damaging a bridge railing and knocking a fence onto nearby power lines. This led to power outages affecting both directions of the adjacent Caltrain tracks, which remained out of service until mid-morning. The two right lanes of southbound Highway 101 stayed closed well into the afternoon while cleanup crews worked to repair infrastructure. No injuries were reported.
How a Jackknife Incident Unfolds
A jackknifed big rig happens when a tractor–trailer loses control and the trailer swings out at a sharp angle, folding toward the cab—forming a V-shape and blocking traffic. This loss of control often results in multi-vehicle accidents or hazardous spills.
Recent High-Impact Jackknife Incidents
- On the 91 Freeway in Yorba Linda, a jackknifed semi-truck caused a multi-hour closure during the morning commute, snarling westbound traffic until lanes were reopened around 6:30 a.m.
- In Las Cruces, New Mexico, emergency crews cleared a jackknifed FedEx semi-truck blocking I‑25 before dawn. All northbound lanes had reopened by 5 a.m. with no injuries reported.
- Interstate 40 in Oklahoma City experienced early morning lane blockages due to a jackknifed big rig. The scene was cleared shortly after 6 a.m.
Why Jackknife Crashes Are Especially Dangerous
- Massive vehicles and blocked roadways: A heavy trailer folding across lanes can immediately halt traffic and cause chain-reaction collisions.
- Hazardous spills: When a rig carries fuel or chemicals—as was the case on Highway 101—spills heighten danger and require lengthy cleanup.
- Emergency delays: In this incident, nearby Caltrain service was disrupted due to damaged infrastructure, affecting thousands of commuters.
How to Stay Safe Around Big Rigs
- Avoid driving in a truck’s blind spots, especially during early morning or evening hours.
- Give large vehicles plenty of space, especially on curves or in slick conditions.
- Anticipate sudden stops and avoid cutting in front of tractor-trailers.
- Adjust speed in poor weather: Braking on slick roads dramatically increases jackknife risk.
