The Hazelwick Flyover construction work is on course to be complete by May 24.
Despite concerns of traffic congestion, repairs to the bridges above Hazelwick roundabout have caused minimum disruption.
A spokesperson for the West Sussex County Council, which contracted the work, said: “Traffic has generally flowed well even during peak times.
“To date we have received a low number of complaints. We have seen in the press that motorists have been surprised by the lack of congestion even mentioning delays have been less when we’ve been doing the work than on a normal day.
“From the start of the project it was made clear that the works were going to be disruptive and motorists were asked to find alternate routes, car share, work from home etc. As a result the traffic delays have been kept to a minimum. We would like to thank the public for this.”