Speed limit could be used for navigation calculation in the case where historical data doesn't exist. Otherwise, some people want it as a safety blanket to warn them when they exceed the number on the sign on the side of the road.

Most experienced and competent drivers should be able to tell you within 20kmh/10mph what the road speed is by road size and location (urban/rural).

Riamus wrote:... I support speed limits not as a way to avoid speeding by accident, but as a way to keep the ETAs and the slow speed warning accurate...

Speed limits should only be used for eta if data is missing. Each segment had significant historical actual speed data in fairly small slices and that along with current speed data is what should be used for eta. And with that data I bet Waze could calculate a pretty accurate actual speed limit. I think bgodette suggested something a while back. And that could be used to manage the more appropriate display of slow traffic warnings.

bgodette wrote:There's also is still/was the issue with displaying ETA vs ETT when crossing timezone boundaries.

Do other GPS systems take timezone into account? Just curious if this is something Waze could tout if they got it to work...

PhantomSoul wrote:I don't see why just the ETA can't be scaled for local time at the destination, especially if the local system determines the UTC adjustment. It would, however need to figure out the time difference between your current location and destination and offset your ETA by that amount.

That calculation requires a substantial amount of data to do on it's own. However, integrating with existing internet/web-based services could definitely assist: there's countess "what time is it <here>?" sites. For the US, there are actually fewer exceptions than I thought. Arizona is the only continental US state to not observe DST, unless you want to travel within the Navajo nation and then DST is observed.

Until 2006, some of Indiana observed DST. Trying to compute your local arrival time when some counties observed it and others did not would have been quite a task.

michail71 wrote:However, I definitely don't think it should be user sourced.

User-sourced would be the only way it could possibly ever have a chance of being accurate.

sketch wrote:...adding a speed limit field for segments in the editor would be simple and easy...

For one speed limit, sure. But as noted earlier multiple times, some segments have 2 or more limits.

In additional the above multiple speed limit types posted, are there some HOV/HOT lanes which have a speed limit different than non-HOV?

paulieg22 wrote:Why not play the 80:20 rule and use the GPS speed information of vehicles driving any particular road. If 80 percent of vehicles are doing between x and y, then its fair to assume the speed limit is y. You'd hope that at least 80 percent of people driving follow the speed limit right?

That could be done and other similar mathery has been posted previously in this thread and elsewhere. The question that comes to mind as @Riamus suggests, is that "is the data provided by Wazers which are likely <1% of drivers going to be able to contribute a statistically relevant and significant amount of data which is identical in proportion to the driving behavior of the larger population?

Can I just add I would like the speed to be displayed for max speed and to be used in the database as today I went through 3 so called traffic heavy where speed limit was 30 and reported speed in traffic was 29 mph. You might be in heavy traffic but if it is moving at speed limit whats the issue. If speed limit and traffic speed and someone tries to report it and it is say within 10% of max speed limit you should be able to not display it. Keep being diverted off a dual carriageway where speed limit is 30 someone even reported heavy traffic and speed was 40 lol.

I cant see why you cant implement it For example where there are speed limit variations you can just have the max speed lmit. I think it would be a really good idea. Some roads i drive on could be 40 30 or 60 mph and if you were not a local you would not know unless you were very observant as some of the signs are in the bushes where the bushes are overgrown.

I love that idea that would stop the heavy traffic reported doing 40 in a 30 lol seen a few of them today I am sure there are some people reporting just to get points but that's a different subject. If speed linked to reporting hopefully stop false reports.