Probably a silly question, but what is the law with respect to how soon you have to deaccelerate once you pass a change in the speed limit? The reason I ask is that today I was chugging along the A3 at 120 km/h when I see an 80 km/h sign, and literally 200m further there was a parked cop car in a siding luckily he didn't have a radar gun.

I'm sure the intention isn't that drivers immediately slam on the brakes but rather reduce their speed gradually.. the question is, how much distance/time have you got to bleed off 40 km/h and comply with the new speed limit?

You should be doing the speed limit as you go past the sign. So, in essence you should see the sign in advance and decelerate so that you are at the right speed as you enter the new limit.

Yep ...beat me too it ... what I was I going to write.
Anything else would be impossible to interpret or enforce.

I've never actually noticed here but on the highways ( motorways ) in Canada there are generally signs warning of an upcoming reduction in max. speed so that yes.. by the time you get to that next sign you better be doing that speed.

That's the key point.

I'm absolutely shocked that someone didn't actually know that and is out there driving on the same roads as me.

I know there are a lot of people on this forum who think they drive much better than they actually do but this takes the biscuit.

Actually - perhaps Castro's trolling?

Thanks Carlos, although I do think this is unfair for those of us with less than 20/20 vision

My car speedometer shows mph, which means I can go a bit faster

More reason not to be on the road.

Have you tried spectacles?

Reminds me of a friend who, many years go, had driving lessons.

"What does that road sign mean?" asked his instructor, pointing to a sign just up the road.

"What road sign? he replied.

He got glasses pretty soon after that.

driving on the motorways in general here is appalling, as you see from the amount of people that go up each others backsides and i am sure the ridiculous speed limits contribute. how can they deem it safe to have a drop from 120 to 80 on a motorway? no wonder.

Awww.. don't be so melodramatic Its true I genuinely did not know the exact legal standpoint but I always slow down the moment I see a speed limit sign.
However it has to be said that Switzerland has an abundance of variable speed limits, and sometimes for no visible reason e.g. driving along the A3 to sunny Zurich on a completely empty stretch of highway with no roadworks in sight, it will go from 120 > 100> 80> 120> 100 (these are variable limit signs, so they change on a daily basis)

BMW driver by any chance?

I was taught that if you are going too fast to react in time, you should be driving a bit slower.

i have to admit, i was bemused by the fact that i was driving in switzerland when i had no idea of the driving rules (right before left, or left before right?) what these funny traffic signs are (esp. the yellow diamond one) and hadn't driven for over a decade and never on the wrong side of the road.

why on earth was i allowed to legally drive??

Guilty as charged m'lud.. although its hard to have an attitude when you drive a baby beemer.. trust me, you ain't getting much respect in a 1er

Happily, the speed limit signs on the autobahn are much bigger ⌀120cm than normal (⌀60 cm), also the first speed limit on the autobahn will be 100 km/h.

PS: On the German Autobahn signs with ⌀84 cm are used. Try to see those when you go >200 km/h.

Thats what I love about threads on EF, it always brings out subject-matter experts from the woodwork

I believe that is the now accepted willy-waving speed

Have you ever seen a 40kph change here? I've always observed increments of 20 when slowing, which isn't that hard or unfair.

In Germany those damned "warning" speed limit signs get me. Though, since I'm up around 200, I'm glad they have the warning before the actual!

How do you exit the highway?
You maintain your speed until you fully move to the exit lane and than you slam on the brakes as the the next speedlimit can be even less than 80, 60 most of the time.
So you do that and not the other?

hahaaaa ....... a friend who`d arrived a short while before me in CH, driving around for her job, commented "The street signs here in CH are SO badly written I can`t read them! I have to get out of my car and go right up to them!"

For some reason she never suspected that her eyesight was diminished! She now wears spectacles.

Scary! (she`s Swiss and had her driving licence before diminished eyesight)