[Tom03]

I have found that I cannot rely upon the speed limit shown on the navigation screen (and on the driver info when set to show digital mph). It seems to be wrong more than it is correct. Google and iOS maps much more frequently are correct. I understand it's a matter of the map database. However, its TomTom. I have a stand alone TomTom unit that is many years old. It includes unlimited map updates, but the last time I updated it was probably a year ago since I tend to use my phone these days. On a recent cross-country journey I pulled it out to see how it does on speed. It is correct most of the time including both highway and city driving. That suggests to me that the TomTom database is accurate. I wonder why the nav in my car that is powered by that database is so often wrong.

???

Tom

 

[backeast]

I'd suggest checking the date of the maps. Hopefully the 2018s were given 2017 maps, but that in turn is probably coming from 2016 data.

The source of that data is ultimately the same. So I'd hesitate to call one conclusively better than the other without a side-by-side on the same roads.

But that said, speed limit errors are not at all unknown - even in the ultimate data sources

 

[z28dug]

Guess that is why pretty much every jurisdiction erects rectangular signs with big numbers indicating the speed limit............>

 

[Tom03]

Indeed they do, though they are not found at every entry point. The Honda Accord I considered buying simply read those big rectangular signs. It seemed odd at the time, but I now realize that would also pick up temporary signs like work zones.

Seriously the issue isn't whether I can just read the signs. It's whether I can generally trust what is showing up there on my dashboard. If not, there really isn't any point to having it.

Re the comparison, I didn't communicate well in the OP, I guess. I was running my portable TomTom and compariing the readings between that and the nav system in real time. The portable was right well over 90% of the time. The nav rate was much lower.

I'd love to check the version, but I don't know how to do that in the 2018. I do know that the USB upgrade option is gone in 2018 and I cannot find a menu option that displays the date of the current map. I guess I'll have Subaru check at my next service.

Thanks

Tom

 

[jnmarshall]

I definitely would not rely on what shows on the dashboard. Ignorance of the speed limit or claiming you car told you so will not get you out of a speeding ticket.
On a more technical note, the speed limit in the database is used to calculate the arrival times, shortest routes, etc... Obviously if the data is inaccurate the calculations AND routing are servery inaccurate. For where I live we have hundreds if not thousands of new roads and I find that address, streets, etc... missing and I can not navigate or get good directions. I checked the map versions. The current tomtom release is 1005 which is q1 of '18. My version is 965 which is q1 '16. So my data is 2+ years old. I just went thru all this with my dealer and SOA as you are suppose to get a 3 year subscription update. However, SOA in their infinite stupidity says the subscription does not activate til your 1 year anniversary date of owning the car So I created my account and noW can't get the activation code from the radio for another year!

 

[jnmarshall]

I'd love to check the version, but I don't know how to do that in the 2018. I do know that the USB upgrade option is gone in 2018 and I cannot find a menu option that displays the date of the current map. I guess I'll have Subaru check at my next service.

Thanks

Tom

The map version is shown on the same screen as the radio information. Home|Settings|General|System Information.
Under the current software version (2.17.43.30) you'll see the navi database version. It will be something like US, Canada, Mexico 965-nnnn-nnnn. The first 3 digits is the version. There's a KB at tomtom that'll provide the date.
The USB upgrade option is NOT gone for 2018. That's the only way to update the navi database. You'll go to https://subaru-maps.com and create an account unless you already have one from another car. You'll need to add your car using it's VIN. You will then be required to activate your subscription. It requires a 20 character activation code from the radio. The site provides step by step instruction on how to get this. But its as simple as Home|Settings|Navigation|Map Update Information. There are two links on the site for a Windows version and Mac updater software that you will need to create a USB image of the update. Since I can't get the activation code from my radio till next year I haven't been able to do this on my outback. But watched it being done on an impreza with the same radio and the tomtom maps.