Weird routing - Tomtom engine or TeleAtlas?

[nlowhor]

I've been using TT Navigator for a couple of years. Most recently I moved to a Treo 700p and found it didn't run very well. So I started shopping for a standalone GPS unit.

I've looked at the Garmin Nuvi, the new Magellan Maestro series, and of course TomToms. I've found one odd issue comparing the routing between these. There's this one route from outside Washington DC to a downtown location that my TomTom Nav has never gotten right. Takes me on a much slower route instead of sticking to highways as much as possible. I've been using this to compare units.

The Navteq based units(Magellan and Garmin) got it right. The picked the route that I would choose to take. I tried a TomTom Go 510 in the store and it got it right. I brought a 510 home and it gave a different route....the slow one. Huh? Why would 2 510s route it differently. Then I got a ONE and it also gives the sow route.

Is this a TeleAtlas vs Navteq issue or something with the TomTom routing engine? Also, why would I get a different route on 2 510s?

For some reason this one route issue bothers me. If it would get it right I would be very happy with my ONE. Otherwise I can't help but consider the Nuvi and the Navteq maps.

Thoughts? Thanks!

 

[46jimbo]

Whenever people use a GPS navigator in an area they are familiar with, they always find that they know better routings than the one given by the navigator. I'm sure that in another situation, someone would complain about the Garmin's routing and prefer the one given by the TomTom.

But we buy these things in order to get us to spots where we are unfamiliar with the best routes. And believe me, I'm quite happy to arrive at my destination, even if I take a little longer than a local guy who knows the short cuts.

If you don't like the routing, just go the way you know best and the TomTom will reroute you.

 

[nlowhor]

Thanks

Yeah, that's what I do. It's just irritating to think that if this route is so poor, how bad are the ones when I don't know where I'm going. I'd just like to know that my device is getting me there as fast as possible.

I really like TomTom and hate the price of the Garmin's so I really don't wanna switch.

Thanks for the response.

 

[Sextant]

It's interesting you mention this because I've seen something weird with routing. For curiousity's sake I had the TT 910 route me home from work. It selected the 11 mile route that takes 20 minutes by its own calculation. I drove the way I know best and it rerouted on the 13 mile route that took 17 minutes by its own calculation. So if it is doing the "fastest" routing why did it chose the longer route by default? I think it is ignoring the time and confusing shortest with fastest. Perhaps this is what is going on with your unit?

I wonder if the store unit had the old version of the maps and routed correctly. The map update that people are complaining about is what's on your unit that you bought and it has the screwy routing issue?

 

[drledger]

I think we have all seem so really strange routing on the gps units we have. I travel a route that tells me to turn where there is no road and there never has been. Within a tenth of a mile tt puts me back on the correct road and we continue our merry way. I have noticed that there are far more errors with the new maps than the old in some areas I travel. Road missing or in the wrong place. I think the concern that was originally posted was that it tt misses in areas we know it is incorrect, is it not also missing in some other areas. I know it does. A couple of weeks ago I was in SC and TT told me to get off the interstate only to route me back up the on ramp. Assumed it was a glitch but when I returned it did the same thing. This time I ignore it and in a second tt showed me on course.

 

[nlowhor]

Which one is screwy?

I think it's hard to say which route is screwy. IMO the better route has only been plotted on the one device I saw in the store. Old and new maps on my Treo, the 510 I tried at home, and the ONE all plotted the inferior route. Why would one unit plot it the better way?

It is very irritating to wonder how many other poor routes we are getting. Makes me want the nuvi 350, but I really don't wanna pay more for it. I like the ONE a lot except this bothers me.

 

[Sextant]

I think it's hard to say which route is screwy. IMO the better route has only been plotted on the one device I saw in the store. Old and new maps on my Treo, the 510 I tried at home, and the ONE all plotted the inferior route. Why would one unit plot it the better way?

It is very irritating to wonder how many other poor routes we are getting. Makes me want the nuvi 350, but I really don't wanna pay more for it. I like the ONE a lot except this bothers me.

As neato as this technology is I would not sit in my driveway here on the East Coast and just let the thing route me to an address in California. I would not rely on any of these devices for something that complicated.

Last year we drove to Florida (13+ hours for us) and I spent a lot of time researching the route and the highways and made sure I was going the most efficient route as well as the safest. In the end it was my route with the waypoints I set on the roads I wanted to travel. In other words I did the real thinking and I let the GPS (CoPilot on my laptop then) make sure I made the right turns and stayed on the right path. I also enjoy being able to see how much time and distance are left on the trip as well as being able to find important POI's. That's the real value for me.

For short trips where I don't know where I'm going I don't mind the GPS unit doing the thinking for me. It's nice knowing I'm not going to get lost. Sure I may have missed the best route but it got me where I needed to be safely. I definitely wouldn't rely on it for a major cross country trip though. Too many screwy variables.

 

[GordonMcKinney]

I agree with the above. People are smarter than these systems... I bought my TT 910 to take me to unfamiliar areas with tucked away turnings and unknown left/right road positioning.

It allows me to drive safely as I'm no longer holding a MapQuest map on the steering wheel and multi-tasking. Oh, and I love the hands free mobile phone feature - bonus!

I turn my TT volume down until I get close to my intended destination, usually where I need the most help and pre-visualization of turns.

 

[lec510]

When I think I am right I veto the GPS, that's the advantage you have over the TomTom that you cannot do with the better half.
Actually on almost every trips starting from home, where I know better, I always have the last say.

 

[RandyR]

Nlowhor, You mentioned that it gave the correct route from the store, but a different route from your home. I have seen the same thing many times. I have seen it calculate different routes on the same street (within a city block) from different directions.

I can give you an example from my Southern Ca vacation last month. We were being routed to our beach house in La Jolla (forgot the street name). Tomtm sent us straight thru a light when we should have turned right. After we went thru the light it started recalculating (within 1 block), told us to turn around and sent us down the street it just missed. Which correctly took us to our cottage.

That mistake was on the main road (forgot road name) that we traveled everyday for a week. Everytime we approached from one direction, it sent us straight, turned us around and then back correctly. BUT, everytime we approached from the other direction (same street) it always had us turn correctly.

I had this same problem in 2 other areas on my trip.

Randy R.

 

[ninjadad]

GPS vs. Map Quest, etc.

I have a TomTom Go 700. When I program in an address for Lamoine, ME from Milton, VT, it has me going south through Manchester, NH and then north to the final destination as the fastest route (8.5 hours). My question is. When I do the same routing on Map Quest and MSN Live Search, it has me going straight across northern VT, NH and Maine as the shortest time (6.5 hours). This same route loads up on TomTom as the shortest mileage route at 9.5 hours. Can anyone maybe explain why there would be such a difference in routing the fastest/shortest time in these 3 programs. I?m not sure which one I should go with. Going across the northern part of these 3 states seems to make the most sense, but 6.5 hrs vs. 9.5 hrs has me confused. Thanks.

 

[nlowhor]

I have a TomTom Go 700. When I program in an address for Lamoine, ME from Milton, VT, it has me going south through Manchester, NH and then north to the final destination as the fastest route (8.5 hours). My question is. When I do the same routing on Map Quest and MSN Live Search, it has me going straight across northern VT, NH and Maine as the shortest time (6.5 hours). This same route loads up on TomTom as the shortest mileage route at 9.5 hours. Can anyone maybe explain why there would be such a difference in routing the fastest/shortest time in these 3 programs. I?m not sure which one I should go with. Going across the northern part of these 3 states seems to make the most sense, but 6.5 hrs vs. 9.5 hrs has me confused. Thanks.

I find that TomTom greatly overestimates travel time....or maybe I just drive too fast. That could account for the part of the difference. It might be of interest to look at the distance of those routes as well.

 

[Renegade-27]

What I find strange is that my TTv4 routes great in NH, perfect trip to NY/NJ area, but when I travel toward Albany NY it gives me awful routes though the roads look right.

Makes me wonder if it the map (which looks correct!) or somehow the routing engine is better in one area than another(???).

 

[ninjadad]

Weird Routing

Thanks. I will take a look at the mileage comparisons. Funny thing, last night I told TomTom to reroute avoiding Toll roads and it came up with the route going straight across the top of the states instead of south and then north. There was only a 7 minute time difference from the original routing, but it was 100 miles shorter. I guess I'll use that route and see which map (TomTom, Map Quest, MSN, etc.) was closest to the actual driving time. I guess it pays to try different routing parameters. Happy travels.

 

[bobaloolie]

As someone said earlier, the TomTom does in fact confuse "Fastest" to be "Shortest." I have seen some very obvious shortcuts... turning into backstreets or neighbourhoods instead of staying on the main road; coming off of freeways one exit too soon etc. all because TomTom's calculations show a few hundred feet of difference, and therefore it concludes that the route must be faster.

My experience with both the Garmin and the Magellan is that it does not make this error nearly as frequently.