A serious accident on the M11 heading south between junctions 6 and 7 is causing long delays.
An air ambulance landed at the scene of the accident. Both sides of the highway were closed at one point.
The northbound pavement reopened just after 9 pm, but the south side remained closed.
Traffic England warned that normal traffic conditions should not return to normal before 12:45 pm and 1 am Thursday.
The Essex police advised drivers to avoid the M11 whenever possible.
Highways England said: "The traffic caught in the closing of the M11 heading south between J7 and J6 is turning and is being released via the ramp. Thank you for your patience tonight."
Motorists went on Twitter to congratulate the emergency services that rushed to the scene.
Meanwhile, the Essex Police Control Room was forced to issue a warning after receiving calls about the incident.
He said: "We are aware of the traffic on the # M11 but call 999 because you are stuck in traffic and we should take you home / water / food / is not what 999 and the police are for. Once we can divert the traffic, we will do it. "