Drivers are being warned to take extra care approaching Chelmsford from this morning.
It’s because of a traffic trial at The Army and Navy junction.
Essex Highways has decided to change the flyover’s traffic direction at different times dependent on real-time flow, rather than the current fixed time switches.
The idea is to be more responsive when incidents and delays cause congestion and make the traditional traffic hotspot more efficient.
Officials say clear signs will warn of directional changes at either end.