M25/M40 junction

[Dr Jekyll]

I've noticed for a while that if the M25 anticlockwise/southbound has a 50 limit on the gantry at this junction, the M40 westbound slip has a 40 limit. Even though the reason for the 50 limit is on the M25 and the slip road limit only applies for a couple of hundred yards. Recently the gantry has taken to showing a 30 limit for the slip road, even when it's 60 for the M25. What's the reasoning here?

[donkmeister]

Can't say I've noticed that... I've used the M25 past that junction a few times in the last few weeks and each time the M40 slip had a higher limit than the M25 (each time I felt a bit jealous as I was in heavy traffic and imagining it must be lovely and empty on the M40!)

[Dr Jekyll]

Tonight it was 40 for the M40 slip and 60 for the M25.

[douglasb]

Last night at about 23:00 it was 50 on the M25 and NSL on the M40 slip (after being down to 40 on the M25).

[grumpy52]

I think it's done to aviod bottlenecks when the motorways actually merge .
It can be pretty hairy if something like an HGV or Coach barrelled up to slow moving traffic at maximum speed .

[DeltaTango]

I've noticed this too OP. It's also the same for the M40 /A40eastbound slip as you're exiting from m25 at j16 going anticlockwise. Almost always showing a lower speed than the m25 gantries even though it's invariably clear. I agree that it's odd.

[Dr Jekyll]

Tonight 40 for slip road to a free flowing M40 and 50 for the M25.

[Magnum 475]

It's similar to the M40 / M42 junction. As you leave the M40 to head for the M42 'north', the limit is always set to 50. It can be 60 or 40 before, and 60 or 40 after, but the first gantry as you exit the M40 is almost always set to 50. Never quite worked out why this is done.