A1 - M25 - A1081
Where is it?
M25 junction 23 and A1(M) junction 1. A vital northern radial route from London crosses the country's most important ring road, the M25.
What's wrong with it?
Another case of the hopelessly underpowered here. Not only is it another of my pet hates, the three-level stacked roundabout interchanges, but it's blocked enough to have that most fashionable of accessories, traffic lights at each entry point. A simple journey from the M25 anticlockwise to South Mimms Services takes the motorist through five sets of traffic lights, with another four on exiting the services to return to the motorway. Just to add to the excitement, a local road (the A1081, ex-A6) joins in the fun.
Why is it wrong?
Basically a desire to be cheap. The A1(M) terminates on the M25 here, but that means the A1 to the south has no motorway restrictions and therefore this junction must provide an exit for non-motorway traffic. Immediately a free-flow junction is made impossible since the A1081 now has to be there.
What would be better?
Something free flow would be good, or at the very least demolishing the services and shifting them somewhere else so the junction doesn't have to take their traffic too. The only way to really improve this would be to upgrade the A1 south of here to A1(M) as well and shut off the A1081 link, finally allowing a free-flow junction.
Right to reply
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These are the most recent comments on this junction. You can see all comments if you prefer.
Tobye needs more space:
I use this junction at least once a week, and every time there is always chaos of some degree, usually it begins on the A1(M) at J2, with queues even reaching back to the Hatfield Tunnel at times. I dread to think what it's like for the A1 northbound, but then they have an extra lane, which would be incredibly handy on the A1(M)! The clear issue here is that the sliproads, all of them in fact, do not have enough stacking space, with the most popular destinations poorly catered for! The whole gyratory should be 4 lanes, try and get rid of a few traffic lights (or at least upgrade to MOVA/SCOOT, so you don't sit at a red for 60 seconds unnecessarily), maybe even provide left hand filters, especially for the M25 (C-wise) to A1(M) (Nbound), surprisingly this is a very popular route! Investment has been made to the M25 above the junction, but as usual with infrastructure money, it failed to work its way down to where it was needed! We shall have to continue with this shambles I suppose, and continue the battle against confused drivers, and risk taking locals weaving like crazy!
Clive is stuck in traffic:
I travelled South on the A1(M) then onto M25 heading East at peak time this morning and it was appalling. At the turn off there is only one feeder lane which had a huge queue of backed up traffic due to the traffic lights. Whilst it splits into 4 lanes eventually the single feeder lane is plainly inadequate at peak times.
Patrickov has a plan:
Just a wild idea after reading the most recent comment... what about making the service's accesses on the M25 EB and A1(M) SB instead? That would eliminate the need of two services, as well as simplifying the junction. The two carriageways connected to the services would have to take some extra load though...
Ian Sergeant writes:
Your comment about moving the services is probably valid, but this would mean the necessity for two sets of service stations, one on the M25, one on the A1(M). I tend to agree with other posters that the A1081 isn't really a culprit - the London Borough of Barnet needs a way out to the A1(M), and this is by far the best one for the vast majority of its residents. By all means create a slip road on to the A1(M) north of South Mimms with a minor road continuing along the old A6 - but I'm not sure that is cost justified. The benefit to the junction would come from the removal of the services.
In addition to the roads you list, there are also a couple of unclassified local roads accessible via the Service Area approach road (one of these, to South Mimms village, can be a useful escape from the M25 onto the parallel B556). So, strictly speaking, the A1081 link is not essential as an exit for non-motorway traffic.
Though I still prefer to avoid using the roundabout here, its current guise has far better flows than formerly.