Slightly dangerous emergency breaking

[beacon39]

Hi Blenny,

I may be wrong but I think perhaps, if you didn't have any flashing red warning lights, what you experienced is not emergency braking but a function of Adaptive Cruise Control which prevents you from 'undertaking' a slower vehicle in an outer lane:

"If ACC detects a slower vehicle in the left lane (left-hand traffic: in the right lane) , ACC brakes gently within the system limits and can thus prevent you from overtaking inadmissibly. The function is active from around 80 km / h (around 50 mph) , but not available in all countries."

Either way, I agree it is a potential hazard. How 'gentle' was the braking? Did you have ACC on at the time?

[Deleted User 314]

Happens a little too frequently for my liking,. Driving along the motorway at a steady 120 and the car breaks to reduce speed to a database point where it thinks the speed limit was 80, which it probably was years back. I notice this most on newer motorways or where there are new junctions.

In general, for me, the database the car is using for such data is very out of date.

Fortunately a quick tap of the foot gets you back to speed but it's a pain.

[monkeyhanger]

Happens a little too frequently for my liking,. Driving along the motorway at a steady 120 and the car breaks to reduce speed to a database point where it thinks the speed limit was 80, which it probably was years back. I notice this most on newer motorways or where there are new junctions.

In general, for me, the database the car is using for such data is very out of date.

Fortunately a quick tap of the foot gets you back to speed but it's a pain.

Not sure whether it's the blame of databases. In my experience, while on the motorway doing 70mph, the camera's will read a 40mph sign up on the sliproad you didn't take and try to slow you down to that, if you don't intervene and dab accelerator to override.

[Deleted User 314]

I would have agreed with you but on the drive from Madrid to Barcelona yesterday (120km/h) aircon to 21.5, outside 31, miles per kw/h (3.9) it braked on 3 occasions on open road.

I’ve had it do as you describe when it sees a sign on the slip as well as brake for me for an exit I’ve decided not to take when the GPS is running.