Home PageFacebookRSS News Feed
PocketGPS
Web
SatNav,GPS,Navigation
Pocket GPS World - SatNavs | GPS | Speed Cameras: Forums

Pocket GPS World :: View topic - TTN3 Overestimating Journey Time
 Forum FAQForum FAQ   SearchSearch   UsergroupsUsergroups   ProfileProfile   Log in for private messagesLog in for private messages   Log inLog in 

TTN3 Overestimating Journey Time

 
Post new topic   Reply to topic    Pocket GPS World Forum Index -> TomTom Software-Only Products
View previous topic :: View next topic  
Author Message
Fuego
Regular Visitor


Joined: 07/06/2003 16:45:14
Posts: 114
Location: United Kingdom

PostPosted: Sat Jun 26, 2004 2:54 pm    Post subject: TTN3 Overestimating Journey Time Reply with quote

How are people finding TTN3 (versus 2) when it comes to over-estimating journey time?

I'm in the UK (set to Miles versus Kms), and a half hour trip, over mixed roads, is likely to be overestimated by around 15 minutes. My road speed settings are at the default values.

My recollection of TTN2 was that it nailed journey times to within 5 minutes.

Is this an issue that TomTom have acknowledged? Anyone know?
Back to top
View user's profile Send private message
Robin2
Lifetime Member


Joined: Nov 24, 2003
Posts: 1441
Location: Swansea

PostPosted: Sat Jun 26, 2004 3:31 pm    Post subject: Reply with quote

It depends entirely on the speeds you set for different types of roads. I have set mine to what I think are realistic, and on a recent 260 mile journey arrived within 5 minutes of the original ETA (after allowing for a stop I made half way)
Robin
Back to top
View user's profile Send private message
Fuego
Regular Visitor


Joined: 07/06/2003 16:45:14
Posts: 114
Location: United Kingdom

PostPosted: Sat Jun 26, 2004 3:56 pm    Post subject: Reply with quote

Care to suggest your current speed settings (or the ones you changed), please? I've been wary of changing these, as I feel that they might affect the routes chosen. Then again, that may be as much for the better as for the worse.
Back to top
View user's profile Send private message
Robin2
Lifetime Member


Joined: Nov 24, 2003
Posts: 1441
Location: Swansea

PostPosted: Sun Jun 27, 2004 11:54 am    Post subject: Reply with quote

I use 65,59,50,47,40,34,31,25 - they seem to be quite realistic for actual traffic conditions
Robin
Back to top
View user's profile Send private message
Howarduk
Pocket GPS Verifier
Pocket GPS Verifier


Joined: Nov 10, 2003
Posts: 241
Location: Essex UK

PostPosted: Sun Jun 27, 2004 8:05 pm    Post subject: Journey times Reply with quote

I have left my settings to default and although it might overestimate the journey time as I progress it works it out. Last night I was coming back from Dover, when I set it the journey time to home was one and three quarter hours.
As I progressed averaging 70 miles per hour the journey time gradually decreased and by the time I got home had estimated the time exactly.

Howard
Back to top
View user's profile Send private message
Fuego
Regular Visitor


Joined: 07/06/2003 16:45:14
Posts: 114
Location: United Kingdom

PostPosted: Sun Jun 27, 2004 10:54 pm    Post subject: Reply with quote

That simply means that as the journey distance becomes shorter, the absolute value that is the percentage margin of error, shortens, until it becomes zero.

Yes, I too can tell you that to get to the spot that you are standing on will take no time at all ;) but if you're happy with your settings, then that's cool too.

Anyway, I'm going to write down the current speed settings and try Robin2's settings (thanks for responding R2). No harm in trying them, so long as I don't have a critical appointment to go to when I test them.
Back to top
View user's profile Send private message
oddsock
Pocket GPS Verifier
Pocket GPS Verifier


Joined: May 01, 2004
Posts: 706
Location: Monmouthshire

PostPosted: Sun Jun 27, 2004 11:43 pm    Post subject: Reply with quote

Robin2 wrote:
I use 65,59,50,47,40,34,31,25 - they seem to be quite realistic for actual traffic conditions
Robin


These are the actual figures I get when I reset to default speed settings in ttn 3.03

dave
Back to top
View user's profile Send private message
Howarduk
Pocket GPS Verifier
Pocket GPS Verifier


Joined: Nov 10, 2003
Posts: 241
Location: Essex UK

PostPosted: Sun Jun 27, 2004 11:50 pm    Post subject: Reply with quote

Has anyone driven the ACTUAL speeds as recommended by TT3 for the whole journey without deviating?
Because it would appear to my limited knowledge of mathematics that unless you do that it will always either over or underestimate because it doesn't take into account road conditions or other traffic or time of day which you as the driver have occasion to do and drive accordingly.

Howard
Back to top
View user's profile Send private message
anarchy-inc
Regular Visitor


Joined: Jun 02, 2004
Posts: 81
Location: P3X-774

PostPosted: Mon Jun 28, 2004 9:48 am    Post subject: Reply with quote

Howarduk wrote:
Has anyone driven the ACTUAL speeds as recommended by TT3 for the whole journey without deviating?
Because it would appear to my limited knowledge of mathematics that unless you do that it will always either over or underestimate because it doesn't take into account road conditions or other traffic or time of day which you as the driver have occasion to do and drive accordingly.
Howard


That would actually result in you taking even longer and the estimate would continue to be adjusted outward. These are average speeds and as such you cannot have 65 as a average without sometimes going above and below. If your car (as mine does) has a trip computer that calculates fuel consumption and average speeds, that might be a way of getting an idea of how YOU drive as opposed to how TT3 thinks everyone does. I will see what mine says tonight on the way home, particularly for the M40.

I too find the ETA to be around 5 mins out for most journeys, but I have yet to test it on a trip over 1-2 hours. This Thursday I'll do a longer trip (5+ hours) and we will see how it works on default settings.
Back to top
View user's profile Send private message Send e-mail Visit poster's website Yahoo Messenger
Robin2
Lifetime Member


Joined: Nov 24, 2003
Posts: 1441
Location: Swansea

PostPosted: Mon Jun 28, 2004 11:33 am    Post subject: Reply with quote

Oops Oddsock! I had tweaked the speeds with TTN2, and hadn't realised that they have reverted to the default values when I upgraded to TTN3! But as I said earlier, they are pretty good overall averages for a long journey, but of course it all goes haywire if, as happened to me last week, you get stuck behind a slow lorry for 3/4 hour with no overtaking opportunities
Robin
Back to top
View user's profile Send private message
Fuego
Regular Visitor


Joined: 07/06/2003 16:45:14
Posts: 114
Location: United Kingdom

PostPosted: Tue Jun 29, 2004 1:31 am    Post subject: Reply with quote

anarchy-inc wrote:
If your car (as mine does) has a trip computer that calculates fuel consumption and average speeds, that might be a way of getting an idea of how YOU drive as opposed to how TT3 thinks everyone does. I will see what mine says tonight on the way home, particularly for the M40.


Ok, that will tell you what you can expect on motorways, although the M25 is a far more variable proposition (with slow and stop being popular favourites) than the M40 and even on the M40 it can depend on which way you're going and at what time of day.

Still, I think the answer is probably to set speeds assuming conditions are good (medium traffic, flowing relatively freely, say), and then take any estimate given (based on such speeds) as a an incident-free ETA, with any slow-downs causing re-calculation.

However, it's much harder to gauge when you drive a route over a mixture of roads, particularly since it's hard to know which road is classified as what by TTN.
Back to top
View user's profile Send private message







Posted: Today    Post subject: Pocket GPS Advertising

Back to top
Display posts from previous:   
Post new topic   Reply to topic    Pocket GPS World Forum Index -> TomTom Software-Only Products All times are GMT + 1 Hour
Page 1 of 1

 
Jump to:  
You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum

Make a Donation



CamerAlert Database

Click here for the PocketGPSWorld.com Speed Camera Database

Download Speed Camera Database
22.034 (27 Mar 24)



WORLDWIDE SPEED CAMERA SPOTTERS WANTED!

Click here to submit camera positions to the PocketGPSWorld.com Speed Camera Database


12mth Subscriber memberships awarded every week for verified new camera reports!

Submit Speed Camera Locations Now


CamerAlert Apps



iOS QR Code






Android QR Code







© Terms & Privacy


GPS Shopping