Cumbria County Council has decided not to allow all types of traffic to use the A591's western shore road and temporary road before it fully re-opens, due to "practical problems".
After two weeks of running shuttle-bus traffic on the temporary road to bypass "The Gap" at Dunmail Raise, a decision has been reached on which traffic will be allowed to use the temporary road before it fully re-opens in May.
It will be limited to: school buses, scheduled bus services, pedestrians, cyclists, emergency services, residents who live between the north and south road closure points, gritters, and essential construction vehicles.
Engineers say opening the western road to normal two-way traffic would lead to gridlock.
An update from Cumbria County Council reads: "The key question was whether traffic could safely and practically be allowed to travel on the road along the western shore of the reservoir, and along the new temporary road. The likely volume of traffic and the nature of the roads themselves were key considerations.
"On average two way traffic flows on the A591 in the months of March, April and May are in the order of 5000 vehicles per day. Given this likely volume of traffic, and the narrowness of the road, highways engineers do not believe the western road could be opened to two-way traffic without causing gridlock.
"To allow the western road, and temporary road, to open to one-way traffic a convoy system would be required over the full 9km route, with traffic moving north and south in sequence. To cope with the peak hourly traffic, 300 vehicles in a single direction, the convoys would need to be over 1km long and would take around 40 minutes to clear the diversion route.
"This would result in traffic being queued for up to 2 hours at each end, making the journey time potentially longer than existing diversion routes. In addition, any incidents of traffic moving in the ‘wrong’ direction on the western road, or a breakdown, would severely disrupt the convoy system causing further delay. Such a system would also hamper access for emergency vehicles and the shuttle-bus which is already proving to be so popular its capacity has been increased. The bus service will continue to be monitored and amended to meet demand."
Cllr Keith Little, Cabinet Member for Highways and Transport, said: “We’ve looked at this very carefully because we understand the impact the road closure is having, but after long consideration we’ve come to the conclusion we cannot allow the general public to drive the road, it is simply not a practical option and would disrupt a bus service that is proving to be very successful.
"I appreciate this decision may disappoint people, but we have to follow the advice of our professional highways engineers. They make these decisions based on many years’ experience managing the county’s roads.”