just tried a route there and it does the best mostly freewy/fastest that I would take. Too bad my TomTom 130 doesn't do that route!
I just requested a route from city center to city center, Austin to Corpus Christi, on both my Garmin 760 and TomTom 740. The result? Estimated travel time from my TomTom was 3:21 and 218 miles. The nuvi? 3:22 and 201 miles. No forced routes and nothing fancy. Not sure why you are getting something different if you are. In looking at each of the routes, nothing stands out as being an obvious bad choice. Without actually driving each, there's no way to positively check one against the other.
So Tim are there any places you know of that have the 930 for a lower price?
just tried a route there and it does the best mostly freewy/fastest that I would take. Too bad my TomTom 130 doesn't do that route!It should mimic devices that have IQ Routes, but it also adds in live traffic data.
Can you assure everyone that you do not have any financial interest in the Garmin devices?
So Tim are there any places you know of that have the 930 for a lower price?You can try bizrate which lists a few...
Yes. :) No financial incentives at all. FWIW, I used your exact Austin to Corpus Christie problem. Where did I make a misstatement? The nuvi computed route was 17 miles shorter but one minute longer than the one arrived at by my Tomtom according to device estimates. Certainly no attempt to be confusing.
Can you assure everyone that you do not have any financial interest in the Garmin devices?I can.
So Tim are there any places you know of that have the 930 for a lower price?I recommend posting this question on the Tomtom GO forum:http://forums.gpsreview.net/categories/9/People like me don't check in the Nuvi forums too often, and there are a few of us in the Tomtom forums who may have good ideas.1) The 920 and 930 are nearly identical, you'll find a 920 much cheaper.2) Try the like below for good priceshttp://www.google.com/products?q=tomtom+920
What counts here is the effective travel time not the estimated one. We already now that the latter is wrong in several cases.
Buying the 920 and separately the Europe maps could be more expensive than buying the 930.
What counts here is the effective travel time not the estimated one. We already now that the latter is wrong in several cases.Agreed. But since nobody has put forth the actual driving time of the route the Nuvi suggests, we're just substituting one assumption for another.
Buying the 920 and separately the Europe maps could be more expensive than buying the 930.The 920 comes with Europe maps so you wouldn't need to purchase them separately.
I did it in the previous page
Do you know if the last three arrive to the same conclusion because they use same routing software, same maps and same speed data, or do they independently arrive to the same conclusion?
Is the 920 the model preceding the 930?
Is the 920 the model preceding the 930?Yes. You can purchase a 920, update the software, and have something identical to the 930. You can do the same with the 720 -> 730. So if you are willing to run the software updates and get the (free) map update then there is isn't any reason to purchase the x30 over the x20. Many want everything to work right out of the box though and would opt for the x30, and the x20 devices are becoming more scarce.
The TomTom refurbs don't always qualify for the latest map guarantee, and what some stores have been passing off as refurbs recently have been questionable as qualifying for that status. I generally love purchasing refurb electronics and saving a little cash, but some of the refurbs I've seen recently are swaying my opinion slightly.
Garmin's recommended route: AUSTIN-CORPUS CHRISTI, TX (I-35, TX-123, US 181, I-37)Effective Travel Time: ~4:30Garmin ETA: 3:05GoogleMaps ETA: 4:45MapQuest ETA: 3:34
Into 7 classes I believe. But it won't affect route choices, only route ETA. :)
If they don't have speeds of various roads, but only classes, then how do they determine "optimal routes' without using that information?
Can I drive from Austin to Corpus Christi following my 760's route in 3 hours and 22 minutes? I don't know. Unless you actually drove it, you don't know either.And honestly, that particular Texas route isn't the real issue anyway. (My guess? I could drive it in 3:22).
Into 7 classes I believe.
5.4 Road classThe main attribute for routing calculation – as it has been mentioned already – is road classattribute. On one hand it is important to prepare data with non broken road network keepingspecific road class, on the other hand it is important to keep well balanced percentage ofroads with highest versus other road class roads.In ideal situation – for usual mixed area (with city and rural areas) – percentage of roadswith specific road class should be:Road Approximate number ofclass roads--------------------------------------4 0.5% - 1.5%3 1% - 3%2 4% - 7%1 10%-20%0 60%-80%Road Class attribute is used as a main indicator for ‘fastest route’ calculation5.5 Speed attributeSecond in importance of attributes used for routing calculation is speed attribute – which isused for ‘fastest route’ calculation.Speedclass Speed attribute Comment----------------------------------------------------------------7 128 km/h6 108 km/h Can be adjusted in MapSource5 93 km/h Can be adjusted in MapSource4 72 km/h Can be adjusted in MapSource3 56 km/h Can be adjusted in MapSource2 40 km/h1 20 km/h0 8 km/h FerryThis attribute is independent of the route class attribute.
So how can the statement "Into 7 classes I believe, but it won't affect route choices" be correct?
Also, is that manual available somewhere? I'd be interested in taking a look at it.
I think that he was only referring to the differences from the Nuvi "learning" your driving habits.
If you really want to dig into the guts of route calculation, check out this Introduction to Route Calculation from Navteq a couple of years ago. Keep in mind it is just an introduction, the real deal is much more complicated. :)
The speed category is a range of speed (say, between 71 and 90 km/h) in which a road vehicle would normally expect to achieve as an average when travelling down that link. This vital information, combined with the length of the link as derived from the link’s coordinates, provides the time to traverse the link without congestion. This is used in the route calculation algorithm’s cost function when the user selects the ‘fastest’ option.
When they say "without congestion" they are talking about unusually heavy traffic, or delays caused by accidents, construction or other unforseen events. Statistically, traffic lights are accounted for.
The odd occasional detouring off a major highway onto a side road or exit for a short distance, only to be routed right back onto that major highway is what concerns me. Some of those posted "detours" make no sense and have no ready explanation...
Finding the faster route has a lot to do with congestion.
Maybe I am ASSuming too much here, but notice how speed classes 3-6 "can be adjusted in Mapsource". I'm guessing that these are also the classes for which the Nuvi "learns" your typical speeds. How can you adjust the speed attributes in Mapsource? Didn't know that was possible.
Finding the faster route has a lot to do with congestion.True, which is what live traffic receivers are for. Otherwise, "[a] vehicle would normally expect to achieve as an average" applies which in determining classification will take into consideration lights, lanes, etc.
Finally someone is more interested in routing than time or speed. IMO the reason you are only hearing of this problem to any extent in this forum and not others is because this forum deals mostly with NA and our mapping. And other users are becoming fed up with the inability of Garmin to correct the problems we are experiencing.In June when we left PHX for Ft. Hood, TX I planned out the route on my new Garmin 765T which had maps 2009 on board. It took me on the EXACT route I planned. (round trip) Which included interstates and secondary roads. Found places to eat at EXACTLY where it said they were and places to sleep EXACTLY where I wanted to rest. NOT one problem... until I got back a week later, plugged in the 765T and POP there was an update waiting and as a good Garmin servant I updated. Since that time the routing has not been right. I traded out for another 765T since Best Buy and myself thought there was something wrong with it. Still not right. Went to the best TomTom at the time and that was a nightmare. (Not routing, just hard to work with) Took it back and got another new 765T. I now have the latest maps and firmware updates installed. Still nothing is right.Like others the unit tells me to get off at one exit and get back on at another. Why? I am already on the interstate why get off it? Known roads that used to guide me around are not there now in the new mapsI had a 760 which I did NOT update the maps, just the firmware, after I saw the fiasco the 765T was going through. Even the routing on it was screwing up. Which it worked good before the updates in June. (I wanted the 765T for the trip to TX since it had traffic and lane assist exits available) Don't see how that could happen but it does.As far as locally? My house number was exactly where it said I was in both Garmin's before the update in June. After June my house address was down the street. My driveway is through a block wall and my car sets in my swimming pool. Known routes to my work was directing me off exits and onto streets that took me a couple of miles out of route when all I had to do was go to the next exit in about 1/2 a mile and go maybe 900 feet to my work place.When talking with Garmin tech support... their solution... "what's the problem you are getting to your destination aren't you?" I asked if I was taking a trip and trying to find some spot in another large city miles away how would I know if the place would be where I asked for? Their comment was "if the unit gets you into the general vicinity then you can find the spot you want with your eyes.. what's the big deal anyway?"Now if I want a spot where I have never been before I consult Google or Bing maps on my computer or phone to see what the correct route is and then use the 765T as backup.I have spent hundreds of dollars for GPS devices from a once reputable company that is not correct. Now I depend upon a couple of FREE mapping applications to guide my way. And the FREE ones are right on the spot!! Crazy huh?
Resetting your nuvi after an application or map update usually seems to correct some of these odd behaviors. Quite a few posters have mentioned their "issue" going away afterwards.