Speed Limit Info - how effective?

The “Speed Limit Info” option is intriguing but I have doubts regarding its effectiveness. Per the brochure, the cameras recognize speed limit signs and posts the information to the heads up display. In other words the HUD shows the speed limit information from the last sign that was passed by and detected by the cameras. However, to me that approach is highly error prone. For example, another vehicle could be blocking the view, or you might turn from a high speed expressway into a low speed residential neighborhood but don’t encounter a speed limit sign for several miles.

Apparently this option has been available in Europe for several years, so it must have been “proven” over that time. However, instead of depending on cameras, I would think that the GPS navigation system could determine the speed limit.

Does anyone have any practical experience with this option? Since its only $100 my guess is that its implemented via software and might be installable by the dealer.

Thanks

GPS can determine location of the car and a speed limit at that location at some fixed time in the past. Speed limit can change any time though, for example, due to construction work.

The GPS database could contain the posted speed limits, but BMW does not advertise this.. and yes, speed limits can change... Either way, it would be hard to get 100% accuracy with this and with something like this if you cannot get 100% accuracy, then at least to me it becomes pointless because if you cant be totally sure then you might as well watch out for the next sign you see, which you would have done in the first place if you did not have the system...

I think it is well worth the $100 as long as you have all the prerequisites. I've found it to be highly accurate.

In generally I follow along with traffic and don't worry about speed limit signs (typical Masshole driving) but it's nice to have the info when the V1 goes off and you've got no idea what speed you should be going

Originally Posted by tim330i

I think it is well worth the $100 as long as you have all the prerequisites. I've found it to be highly accurate.

Very true. I probably would spring $100 for it but since I would not get the $1100 Driver Assistance Package, it is atleast to me not worth $1200. In fact I would get the driver assistance package for the blind spot monitor if it werent the active kind which vibrates the steering, but then I digress... I have zero use for the lane assist.

But officer, it says the speed limit is 45, right there on my windshield.

i thought there is a camera behind the rear view mirror that looks for it

Originally Posted by justinnum1

i thought there is a camera behind the rear view mirror that looks for it

There is a camera and I think the information is also GPS based. They probably work together.

Tim

Originally Posted by tim330i

In generally I follow along with traffic and don't worry about speed limit signs (typical Masshole driving) but it's nice to have the info when the V1 goes off and you've got no idea what speed you should be going

Ah.. Did not realize you were from Boston, and the short time I spent there made me realize that traffic lights are mere suggestions

Originally Posted by rpilot

Ah.. Did not realize you were from Boston, and the short time I spent there made me realize that traffic lights are mere suggestions

I'm not from Boston originally but I've lived here long enough to know how driving works

Originally Posted by tim330i

There is a camera and I think the information is also GPS based. They probably work together.

+1. As mentioned they work in tandem. In case of contruction zones or temporary changes, the camera takes precedence over the sat nav database.

Personally I think it's a pretty neat feature, and helpful in certain states where speed limit changes are not readily posted (lookin at you, VA and SC).

Originally Posted by jben

The “Speed Limit Info” option is intriguing but I have doubts regarding its effectiveness. Per the brochure, the cameras recognize speed limit signs and posts the information to the heads up display. In other words the HUD shows the speed limit information from the last sign that was passed by and detected by the cameras. However, to me that approach is highly error prone. For example, another vehicle could be blocking the view, or you might turn from a high speed expressway into a low speed residential neighborhood but don’t encounter a speed limit sign for several miles.

Apparently this option has been available in Europe for several years, so it must have been “proven” over that time. However, instead of depending on cameras, I would think that the GPS navigation system could determine the speed limit.

Does anyone have any practical experience with this option? Since its only $100 my guess is that its implemented via software and might be installable by the dealer.

Thanks

Hey Jim,

Long time no see! (12 years maybe)??

Let me know if I can assist with an order.

Originally Posted by jben

The “Speed Limit Info” option is intriguing but I have doubts regarding its effectiveness. Per the brochure, the cameras recognize speed limit signs and posts the information to the heads up display. In other words the HUD shows the speed limit information from the last sign that was passed by and detected by the cameras. However, to me that approach is highly error prone. For example, another vehicle could be blocking the view, or you might turn from a high speed expressway into a low speed residential neighborhood but don’t encounter a speed limit sign for several miles.

Apparently this option has been available in Europe for several years, so it must have been “proven” over that time. However, instead of depending on cameras, I would think that the GPS navigation system could determine the speed limit.

Does anyone have any practical experience with this option? Since its only $100 my guess is that its implemented via software and might be installable by the dealer.

Thanks

I read in an article (somewhere) that this works well in Europe because the speed limit signs are circular, and so easily distinguished from other road signs. In the U.S., the system is more prone to error, because it can't always tell the difference between square informational signs and square speed limit signs.

I have this on my 5 series. I live in Finland and it's accurate about 70% of the time.
It uses the navigation system (which has a database of speed limits) and the camera to see if the posted speed limit differs from the database.

first problem is the database is not always correct or up to date. If the camera misses the sign then it uses the database value and that might be wrong.

main problem is that the system will revert back to the navigation system database after about 10km of not seeing another speed limit sign. So here in Finland where the motorway limit changes from 120 -> 100 for the winter, the car will show 100km/h when joining the motorway but then about 10km later it will switch to 120km/h since it won't have seen another speed limit sign for the past 10km so reverts to the database (which in a simplistic way doesn't know about variable speed limits and only holds the summer speed limit).

Obviously the software writers didn't plan for long stretches of road where the real limit is different to the navigation database limit.

I doubt the camera recognizes some finnish signs too - like the built up area sign which is just some black houses on a yellow background without any numbers (this means 50km/h but doesn't state it).

Option was a waste of money in my opinion. I would never order it again.