My Garmin issues re: exiting for no reason

I am sure we all have run across this at one time or another. This post was directly under yours: http://www.poi-factory.com/node/46387 entitled "Well it wasn't a cliff, at least"

I've occasionally seen this with my automobile nuvi and followed the instructions just once. I don't know why our devices do this.

I expect (and would be sad, too, if removed) that the Moving Lane Guides (Active Lane Guidance) is still around for selected exits:

https://www.youtube.com/watch?v=F1gqKXkz9VA&feature=youtu.be

I think that only a small number of exits/interchanges offer Active Lane Guidance right now.

... By moving lane markers you mean active lane guidance? Personally I don't like it but it's part of the map download so unlikely to have disappeared unless you've installed the map in an abnormal way. It's not on every junction though, so unless you know for sure it was at a specific junction and is now no longer showing I don't think you have a problem.

Edit: Craig posted as I was typing

Whenever the unit tells me to exit unexpectedly, I've gotten in the habit of checking the route turn list screen to see if a future turn tells me to get back on the highway again. If so, I ignore the exit prompt.

I don't know what causes this but it happens occasionally on my 3597 as well. Perhaps the unit thinks the exit and entrance ramps create a shorter route? I read in another forum that disabling "My Trends" and "Traffic Trends" will help, but I haven't tried it yet.

Yes, I was routed this way by my 3597. While in a traffic jam approaching the bridge eastbound from the I-95 truck lanes (outer roadway) I took the exit just before the toll booths. A street in Fort Lee, New Jersey, crosses the toll plaza on a long bridge and has an intersection with a traffic signal at the exit ramp.

The nuvi directed me to drive straight across the intersection and continue onto an entrance ramp which went straight into the toll plaza. This detour saved me about ten minutes since it was the most direct route, even stopping at the red light, and I got out of the traffic jam.

Perhaps it was the traffic feature which routed me that way.

dobs108

Had this happen a bunch when traveling through the DC area a couple of years ago. Was quite annoying.

Sometimes my Nuvi would instruct me to exit a road, and then get right back on! It certainly didn't make sense, but may have been calculating "Shortest Route" a bit too literally.

I've tried shortest and fastest route, no difference. Turned off avoid traffic, no difference.
Here's a place that consistently does this:
Start in Escondido, CA. and travel to Poway, CA. along the I15 S.
It always tells me to exit on Felicita, and enter on the same ramp. Not shorter, not faster. I really wish I could figure this out.

... Simulated that route and with 2017.20 it doesn't do it. Maybe something around there interfering with the GPS signal?

Are you using fastet time or shortest route?

... Was using faster.

Zoom in on the segment as close as you can go, then examine the road from the off ramp to the on ramp and make sure there is no break in the line depicting road. Delorme Street Atlas used to be really bad about this.

Does it do this coming back in the opposite direction?

Look at the map and see if you can post the coordinates of the off ramp.

In the far right lane, just after the other lane comes in on the left, there is a peculiar symbol on the road. It looks like a u if rotated left. It's between the directional arrows showing traffic moment south east. I'm in North up. My routing didn't take the off ramp. I have a Nuvi 770 in the truck mode.

a similar problem with google maps, tried to get a route to go from salt lake city to vancouver bc, it had an odd route in oregon.

I've seen this behaviour on numerous occasions with the exit I take when coming home.

I would say at least twice a week I see another vehicle take the exit and then continue straight forward to get back onto the same highway.

I can also confirm that it's not a traffic issue but either a map or algorithm issue.

Keep at it and some one will find a cure for this problem. This is a great site to solve problems.

It is an ongoing problem that has been reported in the forums by multiple users using various Garmin products across multiple map updates. And it is not consistent ... does not always happen under identical circumstances, and is therefore not consistently reproducible. I suspect the flawed routing comes out of the routing algorithm itself, which as we know can give different results for the exact same route under different conditions.

Anyone who has worked on software design and programming of "fuzzy logic" algorithms with many unpredictable complex variables understands that the results are never "perfect", even if you are willing to define and agree on what "perfect" is.

The thing about this kind of program logic is that the more resources you can throw at it with processor power, memory, speed, number of iterations, etc, the better results you will get. The Garmin GPS devices are pretty weak in processing power and other computing resources. I am surprised (even amazed) that they are able to route as effectively as they do. It is not like they have the Google maps server farm working on the solution.

This anomaly has occurred in my 2460 but not in my 2599. A minor reminder to not rely exclusively on technology.

Had same thing twice on my 2555. I was told to exit on a ramp and then immediately reenter. If I skipped getting off and continued on the interstate, I dont know if it would recalculate and try to take me back to the ramp.

Any ideas?

It won't recalculate to take you back to the ramp, unless you've put a viapoint there. This anomaly can happen occasionally as others have observed.

I have had this happen a few time with my 3597 also.

Are these overpasses or underpasses? This could make a difference, although every time it has happened to me it was an overpass - I think. Something in the routing algorithm could be including something it shouldn't. In the case of an RV or truck, the unit could be seeing an incorrect height clearance.

Also, have you checked the "Type of vehicle"? I know that in Basecamp the default is "Walking". This can cause very strange routing at interchanges as the software assumes that there are no sidewalks or shoulder to walk on. Maybe the unit thinks there is no clearance on the side(s) or that there is a "Gap" on the bridge that could cause a problem with motorcycles.

I think that something in the map data causes this since it is repeatable for some users. Still, users should check their "Vehicle" selection.

Easy way to check the routing off and then back on - zoom out and look at the route. That's what I do when in unknown territory.

From my experience dating back to a Nuvi 200 this usually happens when the distance using the exit is less than the distance if you stayed in the main line. It also has to do with the overall route. If, for example you would bear right to take an exit or the road 30 miles up bears right, you will take exits on the right as the straight line distance from your current position is very slightly less than staying on the main line which is to the left. It may be only a foot, but taking the exit places you closer to whatever point the unit has than your current position. It's the same reason the routing will have you exit the mainline and travel surface streets only to rejoin the mainline further along.

I have a screen shot (.png) from the RV760 showing a particularly egregious exit and re-entry from the L.I.E westbound that has me taking the 135 north to the 25, then doing a double clover leaf return to the 495 west bound for no apparent reason. Looking at the scale, this adds at least 4 miles to the route. It's nice to talk about previewing the route, or being familiar with the road and 'knowing better', but it you're driving a RV, towing a vehicle in very heavy traffic (and the Long Island Expressway is always heavy traffic) trying to make it off the island, questioning your guidance is NOT where you want to be. And every time you DON'T take one of these exits, it recalculates, possibly adding more of these 'detours'.
It does not appear possible (or at least easy) to attach a graphic to this post, but if I could, it would be worth a thousand words. It may be that POI-factory limits this because storage would soon be out of hand, I don't know.

What exit did it take you off and what were you using as a vehicle on the gps?

I was using the RV profile on the GPS, the exit was the 135 North, which is the Seaford-Oyster Bay expressway in Woodbury, NY. (found on google maps) Had me going up to the 25 (Jericho turnpike) and immediately return to the 495 WB. The rest is as described. I can email the picture, just can't post it here.

40.799424, -73.484421

This is where the exit was made away from the intended route, I-495 westbound. I live about one mile away and drive this route every day. From I-495 west, ttait exited north on route 135 about one mile to route 25 west about 200 yards to route 135 south about one mile to I-495 west.

In my opinion, this could have been a driving mistake rather than a GPS error. It could have been caused by always sticking to the right lane. I-495 usually has one HOV lane on the left and three travel lanes.

However, between Sunnyside Blvd. and route 135, there is an added right lane formed by extending the Sunnyside Blvd. entrance lane continuously to the route 135 north exit lane about a half mile away. This appears to be a "right lane" on the interstate but it goes directly into the exit.

Once the incorrect exit was made, the GPS recalculated the route properly. The quickest time and shortest distance back to the intended route is described above.

dobs108

Reality strikes. I did not exit, and I usually (almost never) do not drive my RV in the extreme right lane if there are more than 2 lanes just for this reason. If it becomes an exit only lane, people are less than generous yielding to an RV. Driving an RV, I have a fear in NY, of turnpikes and parkways because of low clearance. I also knew that I had to stay on the 495 to reach the GWB.

One of the hardest things to deal with is that I bought this RV GPS to deal with just this problem, and on my last trip to NY it handled everything perfectly and lane guidance kept me out of trouble. (I told all my friends ) And this time it did not.

The problem is that using the RV profile, when you see this, you don't KNOW that the GPS might be trying to get you to take a great, safe, short cut, or has just lost it's mind. The fact that I don't drive this route often only compounds the 'twisted stomach' syndrome I experienced.

This is an example of a GPS routing error. Once again, if I could post the screen shot, all would be explained. The screenshot was taken after the fact by simulating a route from (anyplace in) Mastic Beach, NY. to (in this case) a campground in Stroudsburg, PA.

The RV760 may be alone in this error, or it may be that this error is common to all Garmins with the 2017.20 maps. I just updated to the 2017.30 maps, maybe it will be better. When I talked to Garmin support, they thought it may have been a corrupted download and suggested I re-install the maps. I did that after I returned home and saw the same error in the simulated route, and grabbed the screenshot, sent it to Garmin.
Feel free to simulate this route and report back.

When driving on I-495 west, the route 135 overpass has a 12 ft 9 inch clearance posted. If the RV profile setting in the RV 760 is higher than this overpass, then the rerouting north to route 25 would avoid this clearance problem.

dobs108

A clearance the same as the overpass is not good enough. At what clearance will the RV 760 allow a route under an overpass?

dobs108

I have been in some situations that I am looking at my final destination and the gps inform me to go in a different direction. Next time I will see if there is the problem with the fast route, short route. I will try different settings.

It depends on what the height you entered for the RV. If you told the GPS that the RV was less than 13'6", then it should allow it to pass. You need o check A) what its the clearance of the underpass, and B) how tall did you tell the GPS the RV was.

It's not a case of how much lower the RV is than the clearance. If the bridge is 13'6", then anything that is actually 13'6" or less should go.

Took a drive on an inspection trip of rest areas for mahoney. It was a GoTo, not a route or trip, using a Garmin nuvi 3597 with map NA 2017.20.

I drove westbound on I-495 under the route 135 overpass. There was no rerouting north as described above. Note that the 3597 is a car GPS and does not have the vehicle dimension feature of the RV 760.

dobs108

when traveling between NJ and CT, even though my GPS always directs me to go that way. Always way too congested and the feeder roads are nuts. I always use the Tappan Zee.

Absolutely right!

I even use a "little" detour by the Tappan Zee when driving to NY from Florida. Overall, the distance is a fair amount greater but I still save time ....... and a lot less frustrations!

Tappan Zee was under construction last summer, in fact, the day I crossed onto the island is the day the crane fell.

And, my RV Profile is 12'9" height. I did not exit and had no problem with clearance. I do have a problem when I'm told to exit to a parkway.

As a former driver of a tractor-trailer, I would in no way drive a 12 ft 9 inch rig through a 12 ft 9 inch clearance. I think the RV 760 agrees with me, and the Garmin map had this clearance accurately.

With regard to parkways and other low clearance overpasses, there are literally thousands of such locations in the New York City and Long Island area. I think many of them may be missing from the map so I would never put my faith in the GPS alone. Read the signs!

They are nearing completion of a system of electronic height sensors at some likely parkway locations that activate an electronic sign to "pull over."

This says it all -

http://www.nyc.gov/html/dot/downloads/pdf/trucks_nycarea_par...

dobs108

My garmin does sometimes tell me to take a path I know I dont want to take. I take its advice as guidance....

I had the same issue on a bypass near me... reported it to Garmin as a map error... they confirmed it was a map data error and that it is fixed in 2017.30..

With 2017.30 loaded on my 3597, it no longer occurs..

Report your error to Garmin....

A few years ago I was on an interstate in a totally unfamiliar area to me. Could have been in Texas or Louisiana. I had a route set up which I was following. The 2797 told me to get off at the next exit. It then took me along a small-town downtown street with several traffic lights and then 10 minutes later routed me back on the interstate I had just left.

About 20 miles later the 2797 wanted me to exit again. This time I zoomed out on the screen and saw it was going to do the same again and I just ignored it. The same happened twice more and I ignored these directions.

My GPS's are always set for the fastest route, NEVER the shortest route. I also remember many years ago my old Nuvi 350 wanted to do that once.

So far I saw it happen to me for two reasons:

- road was "broken" on map and has been treated by GPS as "no through" street (it can be interstate as well),
- something got messed up in device and directions were crazy.

For first reason only fix on map can repair problem. For second one often hard reset may help (just backup you data before doing it!).