A21 - M25 - M26
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Ordnance Survey map - Alternative aerial view
Where is it?
Chevening Interchange, junction 5 of the M25. The point where London's orbital meets the A21, a major route to the south coast, and the M26, a shortcut between the M25 in the south and the M20 towards the Channel Ports.
What's wrong with it?
It appears to have been designed by Stevie Wonder Traffic Engineering. The priority route is M25 to M26 - while a fair amount of traffic does go that way, surely the M25 should have priority over all else, what with it being a ring road to 6 milion people and the busiest road in the country. Traffic from Sevenoaks is also badly served: to head east from there and join the M26/M20 route, traffic must use the narrow and winding single-carriageway A25 parallel to the M26 since there's no access to the motorway network eastbound from the A21 here. Kent County Council continue to lobby for a change to this situation, all to no avail.
Why is it wrong?
The M25 wasn't meant to be the through route here. The interchange is built around a section of the once-upon-a-time A21 Sevenoaks bypass, which used to be the north-south route here, explaining why that is a mainline carriageway. When the M25 was built, it stopped here, the A21 continuing north and the M26 continuing east. When finally the ends of the M25 were joined up, it was too late, and the junction had to be adapted. The M25 is now carried on little two-lane sliproads.
What would be better?
First of all, let's have access between the A21 and M26 - a left turn M26-A21 is easy enough to add; then A21 to M26 could be achieved by either shifting the north-western sliproad out a bit to make way for a loop, or tunnelling a new sliproad underneath the whole thing (this has been done elsewhere before). As for the M25, how about giving it more lanes and more priority at merges and diverges?
Right to Reply
E-mail me with your comments.
Richard Crossley says:
Consider that if the UK road numbers were abolished and replaced with a Europewide numbering system, ie the E-routes, the main route would be that of the E40 which is straight through the junction. Just my $0.02 or is that EUR 0.02!
Tim Havenhand adds the following prosecution material:
A point you neglect is that if you want to leave the M25 heading clockwise/south on the A21 is that you have to leave the motorway by a slip road in the outside lane, which is confusing in the least, and if a slow lorry is wanting to get there, probably a danger.
Martyn Feather has trouble heading anticlockwise round the M25:
As you approach the junction, access to the M25 is via the inside lane, which at this point is still full of HGVs heading for the Channel. So it's a slow slog. Or - you could wait to the very end, just when some foreign HGV driver realises he needs to pull out into the middle lane to continue on the M26 - oops too late! Or, as is the case with those unfamiliar with the junction, "surely I don't have to turn off the M25 to stay on the M25?" - "damn... I do!" - and veers straight over the hatched area onto the M25 slip - just. Yep, I've seen all of the above, and they happen on a scarily regular basis.
Finally to cap it all, the slip goes uphill, it divides into two lanes just before the exit. So the inner lane tends to be slow, while the outer is much faster. The inner continues on and becomes the third and innermost lane of what was the two lane A21, whilst the now faster moving traffic feeds into the slower inner lane of the former A21! Great!
Jack Reddall tells a cautionary tale:
Since the opening of the M25/M26/M20 in their entirety, I haven't needed to use the A25, but I decided to stop for dinner at a pub in Brasted on the A25, on my way to Ashford. In 'the old days' I would have had to drive on to Wrotham, and pick up the M20 there, but I thought "ha! There must be a way back onto the motorway system towards Maidstone surely". Not so! Having restarted my journey, I found directions just the other side of Brasted to the M25. Thus began a (short) detour towards the Dartford Crossing, which I was able to remedy at the next exit on the M25. Chastened, I continued (slowly) on the A25 and eventually rejoined the motorway system at Wrotham. Plus ca change, plus c'est la meme chose!
Paul Simons writes:
Conferring with other drivers complaining about this joke of a junction, try travelling clockwise from Dartford, past the point where the A21 peels off. The "M25" is a twisty two-lane feeder road with a very sharp right hand bend to line it up with the Surrey-bound stretch of the M25. I have seen many vehicles struggle to stay on the road while negotiating this bend. Vehicles then start to accelerate to join the M26. M26 traffic has a straight run through, so is normally travelling faster than traffic on the "M25", meaning that traffic in the left hand lane(s) is travelling faster than traffic in the right hand lanes.
Laurie fears for his safety:
Thank you for highlighting this, the most dangerous junction on the M25. What kind of motorway junction is it where you have to take a slip road to stay on the motorway?
One constantly sees baffled drivers pulling off the straight road at the last minute, having just realised that they are about to be drawn inexorably onto the A21.
It's a killer, and should be fixed pronto.
It still has Craig Morris scratching his head:
I travel this route quite often and travelling anti-clockwise I agree that the peel off slip road that joins the M25 to the, erm, M25 is confusing to say the least. Get in the inside lane, as prompted by signs, and end up stuck behind a lorry doing 40mph uphill for the next mile until being allowed by road markings to overtake.
Coming clockwise from Dartford, again you have to leave the M25 simply to stay on the road! But worse, when you rejoin after a sweeping right-hand bend you find yourself in the outside lane. Confused? You will be!
Surely any idiot can see that the M25 should be a ring road, and by definition you should be able to go round in circles to your heart's content without having to negotiate dodgy slip roads.
