From Monday (June 21), both carriageways will be closed from 8pm to 6am between the junction with the A280 Angmering Bypass and Station Road. Work will continue until June 26. West Sussex County Council said the closure will be for drainage works and power crossings. Emergency access will still be available and a diversion will be marked out by signs along the route. Work to widen the stretch of A259 between Angmering and Littlehampton into a dual-carriageway has been ongoing for more than a year, with completion not expected until the autumn of 2022.