Technicians have worked overnight to repair a leak which has shut a major road in Elstree.
Affinity Water has been working as quickly as possible, it says, to reopen Watford Road following a burst water main.
It has been closed since the end of last week causing long delays in Elstree Hill and for people working Centennial Park at the bottom of the village.
The official diversion is via the A41 and Elstree Hill - which has clogged up the exit to the business park.
Jackie Spencer, who works for CACI at Centennial Park, said: "The closure is causing frustration for thousands of employees. The major issue is with the roundabout at the exit. Cars are leaving on the wrong side of the roundabout. Unless something is sorted fast, there will be an accident."
Queues out of Centennial Park this week
Affinity Water and Hertfordshire County Council have both been made aware of the traffic problems - the county council said an additional diversion route will be signposted to help clear the tailbacks in Elstree Hill.
Signposts have reportedly been put up at the Centennial Park roundabout warning drivers to keep the entrance and exit points clear.
#Elstree A411 Watford Road @AffinityWater are continuing to locate & repair the water main. An additional diversion route will be implemented shortly to assist with traffic flow. We will provide further updates as the situation develops. We apologise for the inconvenience caused. pic.twitter.com/pAhzhCn6vt
— HCC Highways (@Herts_Highways) July 17, 2019
Affinity Water was given a permit until July 24 but the latest update suggests Watford Road may reopen sooner than expected.
A spokesman for the company said: "Our technicians have been working overnight pumping out water from the excavation and have repaired the leak.
"We will be backfilling the excavation today and restoring the road surface.
"We realise this has caused traffic disruption in the area and we are sorry for any inconvenience caused. Rest assured, we are working to re-open the road as soon as possible."
A further update is expected this afternoon.
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