Arrival time hopelessly innacurate

[dionk]

Hi, I think this may be an old subject...I travel an 80km dirt road that TomTom says will take 6 hrs. It takes me 2 hrs (sure the map speed data might be wrong). However at the halfway mark (40km) it tells me it will still take 3 hrs to complete the journey. Clearly the TomTom does not use your actual average speed to calc time to destination. This is a hopeless amateurish calc...Gxxxxn does this right and its nearly always spot on with the arrival time. Is there any way to persuade TomTom to change this?? Dion

 

[dhn]

What model TomTom do you have? As well, what application and map version?

Go models with current maps and applications do use IQ routing that takes into considertion 'real-world' historical driving data to result in much more realistic ETA's.

That said, not all maps come with IQ routing data and, for the map you use for your location, it may not be avaialble. Plus, there may not be much previous data for drivers on the dirt road to implement.

 

[dionk]

Arrival time hopelessly inaccurate

Hi, thanks...I am using an XL and I doubt there is any historical speed data for roads in South Africa...however it shouldnt be necessary to use historical road speed data. All TomTom needs to do is calc the average actual speed at the beginning of the trip and use that speed for the calc of arrival time instead of using the map data speed. This is what the opposition guys do and their arrival time estimate is much more accurate than TomTom. The TomTom is better than the opposition GPS in all respects except this one...I cant understand why they dont fix it?? Dion

 

[dhn]

TomTom does not use the posted speed for roads shown on a map in its calculations.

 

[dionk]

Oh...ok, but I still cant understand how it makes such huge errors if its using actual average speed and extrapolating to the destination?

 

[mvl]

In Tomtom's best-selling areas Tomtom maps have IQroutes, so the progammers must have made a conscious decision to trust its map history rather than the speed of the driver.

South Africa is a relatively newer area for Tomtom, so it doesn't yet have IQroutes data. My guess is that it will have the data within a year, but for now there's no way to fix the ETA.

 

[dionk]

Hi mvl,

I certainly appreciate your interest and response.

Are you sure that the XL does use actual average speed, measured at the beginning of the journey, and extrapolate this speed over the remainder of the journey, or at least over the remainder of the journey until the grade of road changes? Having observed the behavior of the arrival time as I drive it appears that it is merely using a default speed for the calc and ignores the current actual average.

Thanks again,

Dion

 

[mvl]

No, it doesn't use average speed (like other brands).

Tomtom relies on the historical speed info from millions of drivers in its maps. For maps that have this info (IQroutes maps), this speed is much better than other algorithms on the market right now.

Since the South Africa map doesn't have IQroutes yet, it uses a really bad estimate based on road class / road width. So until you see an IQrotues map upgrade, there's no ETA fix for South Africa from Tomtom yet.

Certain models from Garmin and Navigon tune to your individual driven speeds, they would be better for ETA until Tomtom releases IQrotues.

 

[Abb0]

This is interesting as I was about to post up a thread on this very subject (after a search of course ).

I live in Houston, Tx but travel a lot with my job and use my TT130s extensively. Last week I drove from Houston to Dallas. It was a drive of 268 miles and judged that it would take me 4.5 hours. Ok, that's an average of 60mph. I can live with that initially as it doesn't know how I drive (although I've had it for more than a year).

However, with 55 miles to go it said that I still had an hour twenty to go. I was traveling at 75mph at the time and had been for some time. WTF???

Don't get me wrong, I love the TT. I think they are far better than Garmin but this is one area where G beats my TT hands down.
maybe a higher spec'd model of TT cures this?

 

[mvl]

maybe a higher spec'd model of TT cures this?

Yes. The 130 and other pre-IQroutes Tomtoms were known to be far worse than the competition in routing and arrival estimates.

With IQroutes, Tomtom leapfrogged the pack and is far superior to the competition. An IQroutes model like the 140 will be significantly better than a 130. On my 5 hour trips, iqroutes is usually no more than 5 minutes off.

 

[Abb0]

Thanks for the reply.

I do like the 130s but maybe it's time for an upgrade

I quite like the 330s, does that have the iQroutes?

 

[mvl]

I quite like the 330s, does that have the iQroutes?

No, the IQroutes equivalent of the 330s would be the 335s. The 340s is easier to find and also has IQroutes.

 

[CynicX]

Thanks for the reply.

I do like the 130s but maybe it's time for an upgrade

I quite like the 330s, does that have the iQroutes?

No, if you like the 330XL get the 340XL. Iqrouting models are labeled as such pretty well...