Tunnel Mode - Please add your model if it offers Tunnel Mode

In my opinion. You can't classify it tunnel mode just because it dims. It could be dimming because it recognizes it being dark.

nuvis have a light sensor. The adjustment of day vs. night is based on local sunrise/sunset, IIRC.

I doubt that any Garmin device has a photo sensor to identify darkness. A quick test would be in daylight hours to take a device in daylight mode into a dark room (or at night, to take the device and place it under a bright light). If it switches to night mode, there's a photosensor somewhere; if it stays on daylight mode, it's based on sunrise/sunset.

I think I've determined with my units that the switch to and from night mode exactly matches the time of sunrise/sunset in my location.

I welcome someone else testing this and reporting back with their results.

As soberbyker and I fully expected, given my previous experimental parameters and the Eisenhower tunnel in a simulated route, the 2460 dims when entering the tunnel, brightens when leaving the tunnel and maintains the simulated entry speed throughout the tunnel with a moving vehicle icon displayed. As in the original experiment, I still advise that I don't know if simulated routes should be used when trying to determine the Tunnel Mode speed and location display inside a tunnel since a simulated route may be different than real life where the GPS signal is lost in the tunnel which may be needed to engage the dead reckoning part of TM.

Darn, I wish I had a nearby tunnel in real life.

PS: Another bonus feature of this Eisenhower Tunnel test is to remind me how to find the SET LOC option which can vary from model to model.

Both my 2460 & 2689 go into day/night mode based on time, not avalible light.

Recharged both units and following results
205w using 2014.10 map - dims in tunnel, maintains entry speed upto .7 mi. then signal loss message
iQue using custom map - no changes
iQue using NA 2009 - dims in tunnel, maintains entry speed for longest tunnel(1.4 mi) on most recent trip

The iQue had it? Doesn't that device date back to 2003 or 2004?

... are we getting confused here as to what tunnel mode means? Is it that the display dims? Is it that your position continues to travel along the tunnel without the GPS saying satellites are lost? Or both? Or something else?

I ran a simulation with my Nuvi 2699LMT.

The closest tunnel to me is the Washburn tunnel outside Houston, TX (according to the Tunnels, USA POI-file here at the factory. That's three hours away, so I opted for the simulation. The map on the Garmin displays the tunnel part of the roadway in a darker shade. I'm colorblind so I won't try to define the colors. Doing the simulation run the display shift to night mode when entering the tunnel and goes back to daytime when exiting.

So I guess I'm one of the lucky ones.

JCA

There is a tunnel about 25 miles south of me on I-71. Upon entering the tunnel both units will dim with the first 100 feet or so. Upon exiting the tunnel the same thing happens. However, if I am driving towards Cades Cove down in the Smokey Mountains, and I enter one of the shorter tunnels, the device will stay the same. No dimming or anything. This leads me to believe that the coordinates of the tunnels are stored in the device. When this info was programmed, the programmer decided that the shorter tunnels weren't long enough to bother with and have TM kick-in. By the time the unit went into TM, you would be out the other side, so you would only see a blip on the screen.

Cassel's post today has me rethinking what we should define as Tunnel Mode. In the post, a nuvi 205W (a 2008 device) with five-year-old maps shows the day/night mode switch but also a loss of signal message and I think a loss of vehicle and speed in under a mile. Is this the first good report of a device with tunnel day/night switch and nothing else?

I'd like to think that we call TM devices those with switch to night mode in tunnels, vehicle icon/speeds in tunnel, and no message reporting a loss of GPS signal in the tunnel at expected speeds but I'm still flexible on what our reports will eventually lead us to. My first post starting this thread which has been updated with the list of models may very well have to be changed considerably.

To me, if the device continues to navigate through the tunnel at constant speed after losing signal, it has tunnel awareness, whether or not it changes to night mode or gives a signal loss message. And according to the reports we are getting from members, this capability was implemented much earlier and into many more Garmin models than I would have guessed.

The iQue 3600 was my first GPS purchased Aug 2003. Used for travels across US, CA, NZ and most of the EU. I have a backup 3600a and a 3200 my son still uses.
It is a capable PDA and having the Palm OS made it a much more powerful device, such as I can search for POI along my route with a variable distance(¼ mi up to 5 mi).
I wish current maps from somebody were still available.

Yes indeed, I'm becoming more and more surprised at how many devices offer Tunnel Mode. I and others have shown that the 3x0, 7x0 and 8x5 series do not have it so it's not universal and I'm still totally in the dark as to when TM was added and if it was a clean addition or if it was staggered with some date where models were being released some with and some without it. Ditto for when map updates started to offer the embedded data and if initially very few tunnels were included and whether it was like Junction Views and School Zones where nearly every map release added more tunnels.

I agree that the main feature is the vehicle/speed in tunnels but I'm still hoping that if present, the auto night mode always accompanies it, and if loss of signal messaging being disabled is even part of Tunnel Mode, that it may also always accompany it. I definitely am hesitant to suggest now that auto night mode in tunnels is sufficient to demonstrate the vehicle/speed presence and therefore auto night mode may well not imply the vehicle/speed feature in tunnels. Hopefully with further users' inputs, especially for the older models like the 1xxx series, we'll learn more.

We do know that map updates have included at least one or a few tunnels in the file data as early as 2010.

If this ever develops into a FAQ, it may well be better to create a list of the older Garmin models that don't offer TM.

Tunnel mode is a function of the map data..and just like older units will not display some detail.. school zones.. posted speed.. all the newer models do.

I still can't find anything about this "Tunnel Mode" on Garmin's website.

You are correct as far as I can tell in that Garmin says nothing about Tunnel Mode just like Garmin says nothing about the Large JCV file and has no FAQ describing how wav files can be used for custom POI alerts, yet we here at The POI Factory use the Large JCV file term all the time and many of us have and use custom wav audio alerts with our POIs which Garmin does not support.

As I said in the other current Tunnel thread, So far, we Factory users seem to define Tunnel Mode as a feature ...

Note that I'm stating that Tunnel Mode is a term created by users here at The POI Factory.

If Garmin did have a FAQ on their site, we probably wouldn't have two active threads here trying to figure out what it is, when it arrived, which devices have (or better yet maybe, don't have) it, when map updates started to include it and whether the number of tunnels has increased over time similar to the introduction of Junction Views, School Zones, etc.

I did the same simulation as in my previous post now with my Nuvi 1390LMT. It has the current map, same as my Nuvi 2699LMT. The 1390 does not change to nighttime mode and the map does not show a different color for the road in the tunnel.

If the tunnel info is in the map data, the 1390 would have been able to show the tunnel on the display, but it didn't. So is the map file on the 1390 different from the one on the 2699?

JCA

After reading all the comments that have been made about this, I am convinced that using simulation to test whether a device is tunnel aware is not a reliable method. Just because a device doesn't switch from day to night mode in simulation doesn't necessarily mean that it is not tunnel aware. I think the only way to know for sure is to observe the behavior when actually navigating through a tunnel. For me that is not possible without a very long drive.

My guess is that the map file is the same but possibly the 1390 doesn't have the ability to use the tunnel data in the map file.

Thanks for the report which is especially good since you also tested a newer model that's Tunnel-aware and because the 1390 may be a model released right around when devices were adding the tunnel mode features.

For now, I'm going to add the 1390 to the list of unaware models but we still need to realize we don't know what's going on.

...that certainly will add to the effort required to figure out what's going on.

The map file is the same for both of the Garmin devices. However, the firmware for the 1390, with latest version at 6.30, hasn't been changed or updated by Garmin since 2016. Therefore, the more advanced 2699's firmware may make use of the same map data differently from that of the 1390's code. Both units implement the Dead Reckoning operation to a certain degree when encountering tunnels, but the newer unit probably has an enhanced algorithm for dealing with tunnels and using the same available map data (e.g., switching the unit into night mode when inside a tunnel.) The more likely reason for firmware differences is that the 1390 was first released back in early-2009, while the 2699 was first available in late-2014. There will be major hardware differences between the two models in their processing and memory capabilities, thereby limiting how Dead Reckoning is implemented along with handling other features of the two units.

Just for reference, the "tunnel mode" of the Taiwanese models are supplemented/(implemented?) with an auxiliary file, tunnel.gpi, which is updated when the map is updated.

When approaching a tunnel, the Gamin units issue an audio warning (in Chinese): "Approaching tunnel, please turn on head lights".

In this fashion, I believe most/all of the Taiwanese Nuvi models support tunnel mode to certain extent. The newer models might have additional features, such as switching the display to the night mode.

Taiwan is a bit beyond my routine cruising territory. It would be a while before I have a chance to verify my statements.

I believe mine supports it.

My GPSMAP64S & Garmin StreetPilot iOS app changes between day/night mode per sunrise and sunset.

I was mis-quoted above. My quote above was this:

"I don't think nuvis have a light sensor. The adjustment of day vs. night is based on local sunrise/sunset, IIRC."

Agree. No light sensor. But I do wonder where the sun rise/set info resides in the unit.

I don't doubt any of your assertions; all quite feasible. Since one of the co-founders of Garmin is a Taiwanese-American, the Taiwan market tends to get some of the more advanced features for initial deployment and field evaluation. That POI file, tunnel.gpi, allows for the audio alerts. These alerts would've been useful for vehicles when automatic headlights weren't as prevalent, but it's so common nowadays that those alerts are so no longer needed; maybe Garmin should revise the alert message to 'Approaching tunnel, please remove sunglasses.'

Any GPS unit has all the location, date and time information it needs from the GPS satellites, along with its time zone map to determine Time Zone and Daylight Saving Time, to readily calculate the sunrise and sunset as needed:

https://www.esrl.noaa.gov/gmd/grad/solcalc/

FYI.

before entering tunnel and returns when I exit. It appears to be gps based as it goes night mode before I enter the tunnel.

Exactly how does this work?

Given that we have soon (hopefully)exhausted the tunnel mode feature.. what about an eclipse mode.. Surely in that moment of darkness one could get lost faster than getting lost in a tunnel.

I never noticed this but will check it out next time I go through a tunnel.

How it works has been the topic of this thread and still unknown as far as I can tell. My guess is, included in the map data is a trigger to do what I describe below in a tunnel.

What it does on the other hand, if you have your GPS set to go into "night mode" at sunset and "Day Mode' at sunrise the GPS will go into night mode as you enter a tunnel and back to day mode as you exit.

traveled to the airport last night and took along one my aging 1450 units. It was night so I could not witness a switch on the screen from day to night. One of the tunnel segments is quite long, maybe two miles. The nuvi showed my progress as we traveled along but must have latched onto the speed when I entered the tunnel. Once I entered the tunnel, I was forced to slow and the GPS kept displaying the same speed (too fast). There's a point where you leave the tunnel for a couple hundred yards before entering the next tunnel. My newer devices seem to be able to obtain a satellite fix again - - very hard to say if the 1450 did. This final stretch of tunnel is shorter than the first section and I got the "lost GPS reception" warning just as I exited the tunnel.

Thanks, I think I'll add the 1450 to the tunnel-aware models.

CraigW, re: 'tunnel' I travel through a dozen times a day. (it's really just a long underpass through Penn's Landing Philadelphia, it does switch to night mode though)

Today I entered the tunnel at 54 mph half way through the traffic was only going about 30 mph I slowed but the GPS still read 54 mph until I was just about to exit when it dropped to the 30 mph I was doing by then.

So the 2689 basically guesses the speed in the tunnel until it can again hook up with the GPS satellite.

My RV760 does tunnel mode.

Thanks for the link, interesting.

I meant does the sun rise/set info reside in the map file, or a separate file (or neither), which then directs the receiver when to switch to day/night mode, depending on where the unit is located.

An interesting question and unless someone from Garmin offers the answer, we can only guess.

Assuming an On-The-Road GPS device can determine sunrise/set anywhere in the world on any day of the year which I think is reasonable, I don't see how a stored lookup table would be what Garmin uses.

I therefore expect that the actual sunrise/set times are calculated using the date and lat/long info from the GPS. A fairly accurate approximation (since we know GPS devices can be underpowered and have so many other things to continuously calculate) can be obtained as described here:

http://www.instructables.com/id/Calculating-Sunset-and-Sunri...

Wikipedia and other links offer much more accurate calculations requring a lot more processing power.

I recall reading somewhere that the device while in "Tunnel Mode" is a bit more sophisticated than one might think, and actually uses last direction and some other tricks to provide a kind of "dead-rekoning" to update the display while in a tunnel with no GPS signal. I apologize for not being able to provide a source for this, but I'm assuming it was from Garmin somewhere. My 2595 changes the display when entering a tunnel. I cannot say for sure if the the vehicle tracks true in the tunnel though. For one thing, I'm usually too busy watching what I'm doing in the usually narrow tunnel lanes. Secondly, tunnels are fairly straight anyway, and I assume the map is accurate so if there -is- a curve, the display vehicle is just going to follow it. What I can say for sure, is that the display is spot-on when leaving a tunnel, so it keeps track of position somehow. It also keeps track of position and "stays on the road" fairly accurately during the occasional loss-of-signal periods in the mountains, heavy foliage and other sketchy signal areas I have travelled through. Pretty slick!

My 2595 accurately and consistently switches the display when entering and leaving a tunnel. The "Big Dig" tunnels under downtown Boston is an excellent test bed for this feature as you can enter, exit and enter more than one tunnel section while travelling along the route. There are also multiple exit and on ramps in the tunnels which the Nuvi tracks pretty accurately. I'm assuming it uses your last speed to do this.

I agree with the above with regard to my 2595. However I would add that the unit also -gradually- dims down in steps after the initial dimming at sunset-time. This always impressed me since I assumed early-on that it didn't have a sensor to read and control the display brightness (no dimming in a dark room during daylight hours). I believe the last "step" is either 10 or 20%; and for those that may not know it, you can take it further and voice-command it to " 0% "too. This doesn't turn the display completely off: just reduces the brightness to "barely on" which is perfect for the really dark "the-middle-of-nowhere" locations.

Wow, I wonder how many models offer the slow-dimming. I don't think any of mine do. It'd be nice.

My 2598 flip to night mode upon entering a local tunnel. Happened to be looking at the unit as I entered the tunnel. Unit flipped back to day mode as I exited the tunnel.

Made a trip with my Nuvi 660 thru the Hampton Roads Bridge Tunnel.

For once my memory was correct. Although the map display did not show a tunnel like my 3597, it did keep the vehicle icon moving along. This was easily confirmed due to the fact that the Fort Monroe peninsula continued to slide off the screen AFTER I entered the tunnel. Also, by zooming out a little while in the tunnel, the south side appeared to slide onto the screen as I approached the exit.

So yes, a Nuvi 660 does have "Tunnel Mode"!

Went through a long tunnel in the Vancouver area yesterday. The speed being displayed did not change even when I slowed significantly.

It won't change, as it has no satellite lock and can't update the speed.

I have found that if you enter a tunnel at one speed and speed up, then the auto icon will jump ahead when you leave the tunnel and satellites are again found.

If you enter a tunnel at one speed and then slow down, the GPS will announce that it "lost satellite reception" before you exit the tunnel. I guess it knows when to look for satellites by using the speed that you entered with. This keeps the announcement from unnecessarily sounding off as soon as you enter the tunnel.

@metricman ... Was it daytime when you drove through the tunnel with your nuvi 660? And if it was, did it shift to night mode on the display while you were in the tunnel?

If a nuvi as old as a 660 is tunnel aware, I am now thinking that all Garmin automotive devices since the introduction of the nuvi support this feature. They may not shift to night mode, but they are aware of the tunnel and maintain movement through the tunnel at a constant speed.

Hey Cool! That's the thread I created! Am I a celebrity now?