A man has been arrested on suspicion of attempted murder after two Sussex police officers were hit by a car.
The officers were carrying out a routine drugs check at the side of the A259 in Littlehampton at about 01:05 BST when they were struck.
Sussex Police said a Mercedes-Benz hit the response officers and a man they were with “at speed”.
All three have been taken to hospital and treated for serious injuries, which are not life-threatening.
A 20-year-old man has been arrested, and police are trying to track down two other people.
Assistant Chief Constable Julia Chapman said: “This is being investigated as a deliberate attack on two police officers in the course of carrying out their duties.
“Their injuries, and that of the man they were with, whilst serious, are not believed to be life threatening.”
A force spokesman said the officers involved were a man and woman.
Police are appealing for witnesses.