A car ended up in a ditch after a crash on the A259 Chichester Road last night (Tuesday), police said.
Sussex Police are appealing for witnesses to the two-vehicle incident at Colworth at about 10pm, which left two drivers with serious injuries.
A police spokesman said: "A black Nissan Leaf travelling north-west collided with a red Skoda Citigo travelling in the opposite direction, causing the Skoda to go into a ditch. The Nissan remained on the road.
"The Skoda driver – a 78-year-old woman from Bognor Regis – sustained serious leg, pelvic and chest injuries, and was taken to Royal Sussex County Hospital where she remains in a stable condition.
"The Nissan driver – a 41-year-old man from Chichester, sustained serious chest injuries and was taken to St Richard’s Hospital in Chichester for treatment."
Anyone who saw what happened, or anyone with dash cam footage, are asked to report it online or phone 101, quoting Operation Abacus.