Southern Water has now removed the temporary traffic lights on the A27 which had caused gridlock today.
Temporary traffic lights on Upper Brighton Road were installed last night while Southern Water teams fixed a burst water main.
The burst was fixed, but the lights had caused major traffic delays all day.
A Southern Water spokesman said: “We’re pleased to say our reinstatement work on the junction of Cissbury Road and Upper Brighton Road is complete and the 3 way traffic lights have been removed.
“We would like to thank road users for their patience and understanding while we carried out this vital work.”