Garmin Speed Limit Accuracy

 

Has anybody received a warning or ticket for speeding because of the Garmin listed Speed Limit? Is the accuracy good for big city speed changes?

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260, 295W, 1490T,2455LMT
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It's pretty accurate

Based on how one's current speed is obtained via satellite, I'd actually trust the GPS's reading over my car's own spedometer. It's astoundingly accurate in my experience. Zero sarcasm here, either.

I drive around downtown Denver, for whatever it's worth.

-Jeff

Although

Although the Garmin speed limit information is very accurate in our travels from Washington to Southern California, it is still up to you to be sure you continue to look for the speed limit signs on the roads.

We find that for highways the speed limit data is very accurate to the point that the limit will change on the Nuvi at the exact point we pass the limit sign on the highway.

In the cities around Palm Springs we find that the Nuvi has accurate speed limit data for most of the streets. In some cases the limit shown is different from the posted limit but we haven't seen any difference of more than 10MPH and usually it will only be out by 5MPH. Neither difference is going to get you in to much trouble.

You must remember that the Nuvi knows nothing about construction zone speed limits and very little if any, school zone, limits so you really have to watch your speed in those areas.

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Nuvi 350, 760, 1695LM, 3790LMT, 2460LMT, 3597LMTHD, DriveLuxe 50LMTHD, DriveSmart 61, Garmin Backup Camera 40 and TomTom XXL540s.

Re: Garmin Speed Limit Accuracy

kkkelleher wrote:

Has anybody received a warning or ticket for speeding because of the Garmin listed Speed Limit? Is the accuracy good for big city speed changes?

No ticket or warning.
I have noticed that locally the Garmin's speed limit is not always correct. Seems to be a local issue. Traveling across the Southwest the Garmin speed was accurate includng the large cities.
Personally, my thought is the speedometer on my car will be the deciding factor should I ever need to prove my case. Not sure I'd have a valid argument blaming the Garmin.

Oops

Forgive me, I misread the OP's question. I thought he meant the speedometer's accuracy. To properly answer the question, I have indeed run into a few places where the Garmin's speed limit doesn't match what the road's is. Granted, the speed limits on the unit have been slower than what the actual speed limit was on the road, so I can't properly answer the question in the context of going too fast, and getting a ticket because of it.

For whatever it's worth though, I certainly wouldn't rely 100% on the GPS's speed limits.

Speed Limits are flaky south of Houston, TX

kkkelleher wrote:

Has anybody received a warning or ticket for speeding because of the Garmin listed Speed Limit? Is the accuracy good for big city speed changes?

Just got back from a week or so in the areas south of Houston. In some places the speed limit indicator changes (correctly) within yards of the speed limit sign. In other places, it is totally off (Garmin says 50, road sign says 35). This was mainly in Galveston/Brazoria counties using the latest map update from Garmin.

So follow Garmin's own advice and don't rely on the GPS speed limit value as being correct.

good, but not perfect

I just completed a trip with my 855. Much of the time, the Garmin Speed Limit was accurate and changed at the appropriate point. But, there were acceptions when it was not consistent with reality or didn't change at the correct location.

It is a nice advisory and I like the feature, but I would not rely on it until proven on a specific road.

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___________________ Garmin 2455, 855, Oregon 550t

Please Clarify...

kkkelleher wrote:

Has anybody received a warning or ticket for speeding because of the Garmin listed Speed Limit? Is the accuracy good for big city speed changes?

Are you talking about the speed limit sign in the lower left corner of the screen that displays the local speed limit for the road you're traveling on, or, are you talking about the speed that the GPS says that you're traveling at when you're in the vehicle going down the road?

NP

--
In times of profound change, the learners will inherit the earth while the "learned" find themselves beautifully equipped to deal with a world that no longer exists...

Speed limit icon not showing yet.

I have been using my 265WT for a few days now and so far the Speed Limit icon has not shown itself on my screen yet. In the Garmin manual it says "you may" get the speed limit icon. Do you need to be travelling on a specific type of road or does this feature just not work in Canada?
I am getting the free traffic alerts OK.

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Nuvi2797LMT (2) Nuvi260,Ford Sync3 Navigation. Captain Cook was a Yorkshire man too.

Not for Canada

bpaine wrote:

I have been using my 265WT for a few days now and so far the Speed Limit icon has not shown itself on my screen yet. In the Garmin manual it says "you may" get the speed limit icon. Do you need to be travelling on a specific type of road or does this feature just not work in Canada?
I am getting the free traffic alerts OK.

Unfortunately for now the speed limit data isn't included in the maps for Canada.

It's explained in the following thread :

http://www.poi-factory.com/node/22143

Cheers smile

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Nüvi 255WT with nüMaps Lifetime North America born on 602117815 / Nüvi 3597LMTHD born on 805972514 / I love Friday’s except when I’m on holidays ~ canuk

Guideline only

I use the speed limit information as a guideline only. If I don't have a clue what the limit is I trust the Garmin until I can find a posted sign. It's helped me a lot when I thought a highway "should" be a 65 mph zone and the Garmin said it was a 55 mph zone. Better safe than sorry but don't give the listing your complete trust. There's NO way they could keep up with all speed limit changes.

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GPSMAP 76CSx - nüvi 760 - nüvi 200 - GPSMAP 78S

Better than expected

I find the displayed speed limit on the Nuvi to be amazingly accurate.
How many times are you driving down the road and asking yourself,"wonder what the speed limit is here".
The Nuvi is very handy at that time.

Thanks

Thanks for quick reply.

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Nuvi2797LMT (2) Nuvi260,Ford Sync3 Navigation. Captain Cook was a Yorkshire man too.

Sent the error report

Thats a bummer. Anyway, I have sent in an error report to Garmin, lets see what they say. If enough people complain maybe they will do something.

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Nuvi2797LMT (2) Nuvi260,Ford Sync3 Navigation. Captain Cook was a Yorkshire man too.

It is important to remember

that the spped limit sign you see on the screen is coded into the map version you have, and is not sensed by the GPS in real time. Therefore, it is only as accuarate as it was coded into the mapping at the time the map was created. If the mapping information is 2 years old then the speed limit information is 2 years old as well. I think some Nuvi models are capable of reading this information from the map data and some are not. It may also depend on the version of the OS on your unit.

It's a guide

I've seen the speed limit on the road vs. the Garmin differ too many times to ever fully trust what the Nuvi is telling me.

Accurate enough for what it is/isn't, imo

Being that the speeds are coded into the road data on any particular map set.. I typically find them accurate here on the east coast/mid-Atlantic area.

When my wife first noticed them on the nuvi, they were accurate enough & changed almost exactly at the location of the road signs.. she was convinced that the signs must have some sort of transmitter on them. razz

--
It's about the Line- If a line can be drawn between the powers granted and the rights retained, it would seem to be the same thing, whether the latter be secured by declaring that they shall not be abridged, or that the former shall not be extended.

Don't trust it

I have been stopped twice, both times in Arizona, for doing the posted speed limit on the Nuvi. I had gotten so trustful of the Nuvi's display of the speed limit that I never noticed the signs.

Fortunatley I was stopped by a female sheriff's deputy the first time outside of Patagonia on Hwy 82, and by a friendly trooper on US 70 or Hwy 77 around Globe, AZ.

Since then I have noticed at least 5 or 6 occasions where the posted speed limit shown on the Nuvi is faster than the actual posted speed limit.

Where I live in the South Florida area, they are pretty accurate though. Although Hialeah has recently lowered the speed limit of several of it's North/South avenue's and the Nuvi is now wrong.

As far as the display of you vehicle speed, it is very accurate on flat and open terrain. If you are in a very mountainy area, the accuracy drops. Generally on an interstate it is correct.

beats guessing

Here near Albuquerque, the displayed limits have so far usually been correct. A couple of modest errors appear in cases where the speed limit differs on the same piece of road depending on direction of travel. Possibly the database representation does not allow for this case, or perhaps the map update people just have not gotten it right.

I think it folly to drop your scan for speed limit signs in favor of relying on the Garmin. But often, I don't spot a limit sign for some time after I have turned on a road, and, less often, I may miss a limit change. Using the Garmin limit as an extra clue can help a good deal in both these cases.

My main regret around Albuquerque is that the database does not carry limits for the lower grade roads. The city streets are generally on a one mile major street half mile slightly less major street grid, with minor streets filling in. The pattern is that all the half-mile level streets have limits display, but nothing below that.

At age 61, with some hundreds of thousands of miles of driving, I have not yet gotten a speeding ticket, though I was once stopped for a tongue-lashing and released with a warning in suburban Boston when I was in college (the officer was on foot!) Using all the clues and not pushing the envelope make me a smaller target than many others out there.

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personal GPS user since 1992

when on the road, I rely

when on the road, I rely mostly on my 765t Speed More so then I do my speedometer. Probably because it's easier to view and I tend to stay under the posted speed limits.

I tend to push the limit

tm1200 wrote:

when on the road, I rely mostly on my 765t Speed More so then I do my speedometer. Probably because it's easier to view and I tend to stay under the posted speed limits.

I tend to do 4 to 6 mile per hour over the posted limit, but there are times when you miss the limit change. Its OK if its going up, but when it goes down I have been given a warning in Texas. My Nuvi 260 does not show the speed limit, so I am looking for justification to upgrade my unit. I will probably wait a while until my next trip out west. Thanks for all the replies.

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260, 295W, 1490T,2455LMT

garmin speed

I noticed also that my car speed says 40 and my gps says 43. this variance is the same wether in the ciry or on freeway, where ever the posted speed shows up. it's the first thing I noticed and wonder why they were'nt they same

Verifying speed accuracy

thewizardman, there is a lengthy discussion on accuracy of the GPS compared to speedometers in this thread: http://www.poi-factory.com/node/6695. My post on page 5 (near the top) describes how you can use a stopwatch and mile markers to check speedometer accuracy.

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Alan - Android Auto, DriveLuxe 51LMT-S, DriveLuxe 50LMTHD, Nuvi 3597LMTHD, Oregon 550T, Nuvi 855, Nuvi 755T, Lowrance Endura Sierra, Bosch Nyon

Pretty darn good!

Mostly accurate in the North East thus far. Of course changes can and will occur daily and it will take time for updates to catch up. That and it won't note slow downs when long term/short term construction is taking place generally. Nice feature 95% of the time!

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Garmin Legend, Quest, and Nuvi 350, currently Nuvi 855 (and my Palm Pre w/ Sprint Nav)

your wheels are worn down.

thewizardman wrote:

I noticed also that my car speed says 40 and my gps says 43. this variance is the same wether in the ciry or on freeway, where ever the posted speed shows up. it's the first thing I noticed and wonder why they were'nt they same

your wheels are worn down.

Verifying speed accuracy

My jeep is 3 mph under my gps. I have even had it check with police radar and portable radar trailers that they set around the town. Most vehicle mph gauges are all off I use the speed on my gps more than anything.

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johnm405 660 & MSS&T

Carpool lanes

Speed limit was 10 mph higher in carpool lanes than the normal speed limit, which is what garmin showed...

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nuvi 250 --> 1250T --> 265T Lost my 1250T

Garmin speed limit very

Garmin speed limit very accurate but doesn't reflect the update posted speed for contruction areas.

That's incorrect

whoever wrote:
thewizardman wrote:

I noticed also that my car speed says 40 and my gps says 43. this variance is the same wether in the ciry or on freeway, where ever the posted speed shows up. it's the first thing I noticed and wonder why they were'nt they same

your wheels are worn down.

Actually, that would be the opposite happening. The speedo is pessimistic, and it is fairly common. Larger rim / wheel combos are one of the causes. The GPS is always correct.

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nüvi 3790T | nüvi 775T | Those who make peaceful revolution impossible, will make violent revolution inevitable ~ JFK

Speed limits

Those speed limits are incorporated into maps and are not necessary corresponding to speed signs. So you can't depend on them 100% for actual speed limit. If speed limit is changed it will be get it right on maps after next update, so be careful and pay attention to actual signs.
To see that those values are prerecorded on maps it's enough to drive into smaller residential streets and you'll see, that speed limit will not show on the screen. Same happens when there is work zone, it still shows speed limit as it was before construction.

Posted Limits - MI Experience

I, too, have noticed speed limts being off in smaller communities around the state of Michigan, so I only use the Garmin's posted speed when I am unsure what it really is. Major roads, however, have been spot-on. I'm impressed with the fact that the Garmin posted speed changes within feet of the sign on the road (I know, little things amuse me).

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--- GPSmap 60CS, Nuvi 650 & Nuvi 1490T---

Speed limit

Ours has been fairly close to the posted signs around Nashville, but I wonder how often the data is updated verses the signs being changed

Changing speed limits

Since the start of this thread I have been watching the Nuvi posted speed limits in the Phoenix area (a good idea here). When I first used the gps I thought the limits posted on the Nuvi were very good. While watching them now, well you had better not rely solely on them. I am seeing more and more off by 5 mph. Major roads are good though.
How to keep these posted limits up to date seems to me to be a very hard job.

Map version.

Chaspoi, just out of curiosity, what map version do you have? If you have upgraded maps, do you ever see speed limit changes or corrections in the maps for your area?

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Alan - Android Auto, DriveLuxe 51LMT-S, DriveLuxe 50LMTHD, Nuvi 3597LMTHD, Oregon 550T, Nuvi 855, Nuvi 755T, Lowrance Endura Sierra, Bosch Nyon

re: Map Version

alandb wrote:

Chaspoi, just out of curiosity, what map version do you have? If you have upgraded maps, do you ever see speed limit changes or corrections in the maps for your area?

I have the most recent, 2010-30. I am certain that those stats are updated along with new roads, interchanges, etc. But just like roads and interchanges, not everything gets updated on every map update so there is no way to tell if those in your area have been other then watching.

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--- GPSmap 60CS, Nuvi 650 & Nuvi 1490T---

2010

alandb wrote:

Chaspoi, just out of curiosity, what map version do you have? If you have upgraded maps, do you ever see speed limit changes or corrections in the maps for your area?

I have the first version of 2010.
There are a lot of road upgrades going on in the Phoenix area. Every new intersection requires new speed limits. Keeping up would not be an easy job.

Accuracy for Phoenix area confirmed

Regarding chaspoi's comment about Phoenix, I can confirm for the Scottsdale area. I've been using my Garmin to get acquainted with this area for about six weeks and have noticed that the speed limit is usually accurate, especially on major roads, but can be off by 5 mph. When I don't know the limit, I assume it to be 5 mph less than that reported by the gps. That has worked for me so far.

I used the gps in the Denver metro area and on the trip to the Phoenix area and noticed that it seemed to generally be accurate but didn't use it long enough to be more definitive.

I've got map version 2010.20.

Accurate

The speed on the garmin has been extremely accurate in my experience.

I wouldn't say it was 100%

I wouldn't say it was 100% accurate but most times right on mark even off the main roads in central FL.

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Charlie. Nuvi 265 WT and Nuvi 2597 LMT. Android Here WeGo - Offline Maps & GPS.

Pretty Accurate in NY

Its pretty accurate but I still look for the posted speed limit signs in case there are changes that have not been updated on the Garmin. Of course with road construction, you need to follow the posted signs and forget about the Garmin.

Accurate

I've seen a few times where it was inaccurate, but it's usually right on.

Accurate

thomas8093 wrote:

The speed on the garmin has been extremely accurate in my experience.

I thought my vans speed-o was out by about 10km When I turned the garmin on it was 10 km out. I tried it in the car and it as out by 3km out.

ohwogo nuvi 750

Speed limit

No ticket. My observation is that it usually changes wthin a few hundred feet of the speed limit change. Sometimes a rural road will have a speed limit of 35 mph and Garmin will show 45 mph. Also it doesn't know when school zone speed limits change during opening and dismissal.
I suggest look for signs and check speed limit on the Garmin in between.

My 255W is pretty accurate,

My 255W is pretty accurate, but then again i go by the actual speed limit posted on road and not the a GPS!

Garmin Speed

I would trust the speed that your Garmin is indicating that you are doing over the speedometer in your vehicle. I have confirmed several different GPSr's on my movin radar unit in my patrol car and all of the GPSr's are exact to the moving radar unit.

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Geojeep

my trip

I just traveled from Vermont to Florida and my Garmin 265WT read about 2 mph less then my speedometer. When I get back hom, in March, I am going to do a laser test on my vehicles speed to see which is really correct !!!!!

Its a good bet

that the Garmin is correct and speedometer is fast.

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Alan - Android Auto, DriveLuxe 51LMT-S, DriveLuxe 50LMTHD, Nuvi 3597LMTHD, Oregon 550T, Nuvi 855, Nuvi 755T, Lowrance Endura Sierra, Bosch Nyon

This has been very helpful

This has been very helpful since i want to get a new nuvi and i wanted to have this on it> my 680 doesnt have this.

GPS Speed Control as a feature

Seen in Thailand, where tour buses are notorious for going at excessive speed worrying tourists, painted on a large bus as a "feature", like Aircon, etc.: "GPS Speed Controlled"

Going to go with the Garmin

My bet is that my speedometer is off,,I moved it to a friends car and both the Garmin and speedometer read the same. I also just replaced the tires, I'm wondering if that also contributed to the difference it reading.

do any PC-based Navs tell Speed-LIMIT ?

I tried the Garmin nRoute, which runs on the PC, but alas, it only shows speed, not speed limit.

Q: Are there any PC navigators that show speedlimits?

Rgds,
Jim Pruett
http://www.wikispeedia.org

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