My first encounter with phantom road closures

[danham]

Last night I had my first encounters with phantom road closures really messing up a route. In the cage, headed to Boston from Cape Cod to attend dinner and a show. I let the XT plan the route, whose destination was the Boston Common Parking Garage at zero Charles St. First off, neither Google nor Garmin can find zero Charles St, though both can find the parking garage entrance at that address.

The correct way to get there, which Google shows, is to take a left exit off 93 northbound heading toward South Station, then bear right toward Lincoln St then turn left on Kneeland Street. Good old Boston cow paths. We had plenty of time, so I decided to try the XT's suggestions instead. Bad move. It did not call for taking that exit and as we approached same it flashed a red warning that the road was closed to vehicles and tried to re-route. The road was not closed and the route it chose was nonsensical. By then we were in the tunnel and lost satellite signal. Out of the tunnel and off 93, as we used Google to get back on track, the XT put up an urgent and incorrect warning that we were going the wrong way on a surface street. At which point it began to behave like RUT.

So was this mess caused by faulty traffic info, map errors, or something in the XT's brain? BC does it properly, using the same map.

After the show, the XT did an excellent job of getting us out of Boston and headed south on 93. Glad I wasn't on the bike.

-dan

[jfheath]

Road closures come from the Drive App relaying information from (I assume), a central database. Usually the information is accurate as regards location, but it relies very heavily on the people who submit the closure information.

So a well coordinated road closure will probably be recorded accurately and the dates will be spot on. A group of people leaning on shovels fixing a hole in the road, when they can get hold of the person who was supposed to order the tarmac, probably less so.

Not everyone in the chain realises what the term 'real time information' means. Or that the installation of traffic lights is not the same as a road closure. By that I mean that when the road is re-opened it is just as important to have the information updated immediately, as it is to record the closure. We often have night time only closures when work is carried out on busy roads. I have seen these displayed as full time closures on the XT screen.

The XT and XT2 have pretty impressive features for displaying additional information about closures which are worth checking against other sources - particularly in places like Scotland where a single closure can result in a detour of more than 100 miles.

And then some satnav software designers treat it as if it is 100% accurate 100% of the time, and then re-organise your route without you having any say in the matter.

BUT. Today while doing some other testing - I was simulating a route and I wanted it to continue. I think I was recording at the time, but I know where it was and can easily be reproduced. But I half read the message as I dismissed it. I think it was asking if I wanted to divert. If it did, then for the XT2, that is new.

The XT ? i just turned off the feature.

[Peobody]

@danham, I am sure you've seen my posts about the inaccuracy of the traffic notifications on the XT. I have also encountered phantom road closures. I have had enough valid ones to consider the traffic feature useful although I suspect I would change my mind if I experienced what you describe. The aggravating thing is that you don't have the option of telling the XT to ignore the road closure and continue on. I wish road closures where presented as advisories, with the choices of allowing the satnav to re-route or not.

[rbentnail]

Seems like I handle road closure notifications differently from others: I ignore them. With the XT's Auto Recalculating set to prompted, I simply say NO to recalculate and ride my route as if there's no issue at all. If it's closed, fine, I follow the detour signs until I'm back on route. If it's not closed, I continue as usual on route. Either way the XT will catch up when it decides to and without recalculating the rest of my route.

IMHO use your brain first and the gps second. To me, he thing is a GUIDE, not the LAW.

[Rofor]

@rbentnail - for a 'normal' detour, i'm completely on your side! Just follow the signs on the street to go back to the original route, than the normal routing will continue as usual - BUT: sadly that didn't work, when a complete(!) road closure is signaled via the Drive app! In that case, the Zumo XT starts an automatic recalculation, completely ignoring whatever the settings in the unit are! You have NO(!) choice to stop this recalculation and you'll not be asked if you want to do this recalculation!

I had this twice times since buying the Zumo XT, when it appeared in 2020, both times it was a completely false information - this is heavily discussed here in the german speaking countries at Naviboard.de. Garmin is aware of that fact and Garmin says 'It's a feature, not a bug'...

This is the reason, why i have completely disabled traffic information on my Zumo XT - for me, the user should always(!) have the last word what the unit should do and i can't go here with the sight of Garmin to that fact...

[jfheath]

Garmin is aware of that fact and Garmin says 'It's a feature, not a bug'...

Yes. That is an old programmer's joke. Their programs are full of 'features'.

I use the word 'Feature' quite a lot when I am talking about oddities in the behaviour of my satnavs.

Curious that when the stanav spots a faster route because of traffic delays ahead, it asks if you want to detour, and it gives the expected amount of time it will take / save. You get the choice. Why not 'road closures'. Road closures are sometimes there. Often round here they are just night time closures, or in one recent case when it was just for part of a day when a cycle race went through.

I'll put a suggestion in.

[danham]

Here is how Google portrays the crazy interchanges just north of where the XT insists the road is closed. I wonder if the complexity contributes to the problem?

Screenshot 2024-11-14 at 8.53.27 AM.png (402.14 KiB) Viewed 671 times

-dan

[jfheath]

I'm putting a cross - top right.
Your turn.

[danham]

Good move. My turn. Notice how the route beyond the closure symbol has turned black. WTF?

13642.png (1.21 MiB) Viewed 669 times

-dan

[Peobody]

I wonder if the complexity contributes to the problem?

I have seen mine get confused by two situations.
One is parallel roads separated only by Jersey barriers. I can think you are on one road when you are actually on the other.
The other is parallel roads at multiple elevations. The XT just can't tell which road you are actually on.
In both cases, if it thinks you are on a different road than you're actually on you get a recalc response depending on what the setting is. Mine is set to "Prompt" so I get the 'off route, do you want to recalc' popup.