Arrival Time....again!

[dionk]

I am aware that this is an old topic but it really bugs me! My research of the forums shows that TomTom uses map speeds to calculate arrival time which results in a very inaccurate (pessimistic) arrival time, particularly on rural roads. It does not correct the estimated arrival time using the actual average speed that the driver is traveling at as most (all?) of the other GPS navigators do. Yes, I know TomTom thinks this is superior but its not. TomTom has invented a complex method of improving the estimate using data from other users but this service is only available in a few countries. So us poor sods who live in most of the other countries just have to live with this very inferior feature. Please TomTom...cant you develop an update for us poor sods that we can download that will use the average speed method. It could become a user-selectable option on the screen as to which method is used. It really cant be that difficult...after all Time (to destination) = Distance (to go) / Speed (actual average). Come on TomTom....DO YOUR LOYAL CUSTOMERS A FAVOUR!

 

[pianoCM]

Are you talking about 3-year-old firmware?
Nowsaday, with IQR then IQR v2, TT EAT (estimated arrival time) is most accurate in the gps world.
Maybe your unit doesn't have that feature?

 

[canderson]

Are you talking about 3-year-old firmware?
Nowsaday, with IQR then IQR v2, TT EAT (estimated arrival time) is most accurate in the gps world.
Maybe your unit doesn't have that feature?

As I began to read, I had the same impression, but as I read further, I noted the words "rural roads". I don't have any idea how much data TeleAtlas requires for a given road section before it begins to slice and dice the average speeds across the time and days of week, but it seems possible that a specific "rural" road might not be incorporated into the IQ system for quite some time, if ever.

I would note that previous to IQ, a manual addition by the user of the actual speed limit seemed to have quite an impact on ETA. On the assumption that this may still be useful, I would recommend to the user that he add the speeds on his favorite pieces of road by "Map Correction" to see if there is a commensurate reduction in the ETA.

 

[dionk]

Hi Guys...thanks for the interest! I'm using the TomTom in South Africa, I have the latest maps loaded and all corrections. As far as I can ascertain IQR is not an option in this country. Hence my plea for TomTom to provide an update using average time to calculate Arrival Time. As an example, I use a rural road that is good for traveling at 40-60km/h. TomTom does its arrival time calc based on 15km/h ie 6 hrs estimate for a 90 minute trip. My old Garmin got the timing spot on using my actual average speed. I'm a loyal customer having just bought both my daughters a TomTom....pease give us a fix!

 

[Arno]

I agree with canderson. Try to set speed limits with map corrections.
If I am checking A .. B routes for some questions here I have often received the
warning Not enough data available to use IQ Routes (or something to that effect.

 

[grwebster]

Wonder why they would use such a low speed. The trouble with using you average speed is that there is no guarantee that you will continue to go that speed for the remainder of the trip.

 

[dionk]

I updated the route speed to 40km/h but it is still showing 4hrs39mins for an 86km sector = 18.5km/h. I think the real issue here is that using map speed in city driving is probably the most accurate method due to traffic etc which can change one's average speed. In fact I must say the TomTom's Arrival Time is pretty accurate in the city. However, I use my TomTom primarily for open road driving where its usually possible to maintain an average speed. On the open road the map-speed method really sucks (note no IQR available). Guys, in a country where there is no IQR, surely making the average speed calculation an option would be a huge plus for very little effort? Pleeease!

 

[vlakvark]

Arrival Times on TomTom

I agree completely.

I am on my second TomTom now and even on the first one the first thing in the display that I switched off was the ETA. I also drive on a lot of rural roads in South Africa and now I just calculate the ETA in my head.

I would also love to have an ETA based on average speed, even thought I might not maintain that speed. I am sure that the ETA will be more accurate than it is at the moment based on fixed speeds.

 

[Arno]

I also drive on a lot of rural roads in South Africa and now I just calculate the ETA in my head.

I just used Google from Prieska to Kimberley, 235 km, 220 minutes on R357.
That is not exactly a rural route but I don't know anything about roads in RSA and wounder it just a shade over 60 km/h is too slow.
Google may have used Tele Atlas but then again, it could have been Europa Technologies.
TomTom route Planer , right now 2200h local time) adds 6 more minutes.

 

[GarCor]

I realize that I am not traveling rural roads when I travel from Nova Scotia to Florida but mostly interstate.
I am amazed just how accurate it arrival time is. We we hit the road in the morning we don't stop for anything other than restroom and fuel stops. Most of the time I travel at no more than 6-8 kL over posted speed.and that just compensates for the restroom /fuel stops.
I usually arrive at my destination after 600-700 miles within tomtom's time (+ / - 5 min ) that it had posted at the start of our day.

It also proves to me that these people going by me like I am stopped might, Just might get to the same destination 10 min before me that is if they don't pick up any flashing blue lights ;-)

 

[drledger]

I traveled between my home and northern Ohio on a regular basis. I found that when I left home I could tell my family my arrival time based on TT calculated time plus 30 minutes for a lunch stop. I would never be more than ten minutes off. My drive was a mix of 60 percent Interstate and 40 percent secondary roads.

 

[vlakvark]

I will admit that on the highways (interstate) the ETA is fairly accurate. It is when you go onto secondary or rural roads that the tomtom falls short on the ETA, and this is the roads that I mostly use.

This is by far not a dealbreaker for me, it is just that the calculation for the ETA, using the current or an average speed, (as was mentioned earlier), is so easy. I had a Garmin Nuvi before that did a MUCH beter ETA than the TomTom.

In any case, I still love my TomTom, and it keeps the grey matter busy with mental calculations of the ETA.

 

[mvl]

Tomtom will release IQroutes on updated maps as they get enough data in a country. As more Tomtoms are sold in South Africa and more customers enable the "submit anonymous data" feature, it's maps will eventually have IQroutes added.

Because IQroutes is a much better predictor of arrival time than personal speeds in most cases, Tomtom doesn't bother to write a personal speed algorithm in its software. So you'll just have to wait some time until an IQroutes map becomes available. My guess in South Africa is about a year.

Editing speed limits only impacts the screen display and overspeed warnings, it does not impact arrival times.

 

[gatorguy]

Because IQroutes is a much better predictor of arrival time than personal speeds in most cases, Tomtom doesn't bother to write a personal speed algorithm in its software.

While you might assume that's the case, it's not true. My 3-year old nuvi 760 is just as accurate estimating my travel time, and quite often even more so when used alongside my TT740. Basing my trip times on my personal historical driving speeds (Garmin) is a very good predictor. TomTom's IQR's value compared to other devices is the potential for better route choices, which as a side benefit obviously would have a more accurate travel time attached to them or IQR wouldn't be effective. In Tampa and Orlando my TT may find a better route choice than my Garmin depending on the time of day (Perhaps 10-20% of the time?) But my TomTom still doesn't consider how I drive the country roads, or how fast I'll travel our local interstate. Since my Garmin does it leads to very accurate travel time estimates for the routes it computes.

 

[mvl]

The classic debate...

Is the ETA based on your own experience more important than the ETA based on everyone's experience.

In the South Africa example, clearly a Garmin with your own experience beats a Tomtom with no experience.

In areas where IQroutes is covered, it really depends on what the neighborhood is like.
- If big and congested with lots of traffic and lights so your driving habits don't make a difference, then IQroutes is more relevant.
- If rural places that you go to often, so your own speeding habits matter more than what others do, then Garmin personalized ETA is better.

 

[gatorguy]

You might have missed my point MVL. Garmin's logging of personal drive times over various road classes won't make any change in route computation, unlike IQR on a TomTom. So other than ETA, it really has no effect on navigation. TomTom's IQR, on the other hand, is in integral part of navigation and does affect route computation. Overall, TomTom's IQR is of much more benefit than Garmin's inclusion of personal driving statistics. The only point I was attempting to make is that from a pure estimation of travel time based on what route the device computes, Garmin will often be more accurate on ETA. From the view of which device offers the most effective route most of the time, Tomtom with IQR definitely wins in the metros and is nearly on par with Garmin in rural areas. Comparing to a Tomtom model without IQR, I'd give the edge to Garmin overall on route quality. IMHO, there's no reason I'd consider a TomTom without IQR.

 

[mvl]

Yup - I agree. Without IQR, the only unique value is of Tomtom is mapshare (and HD traffic in Europe). Garmin, in my opinion, does everything else equal to or better than Tomtom.

Yes, I got the ETA point:

- Garmin takes personal speeds into account for ETA calcs, but not routing.
- Navigon MyRoutes and my Honda Nav take personal speeds into account in both ETA and routing
- Tomtom doesn't take personal speeds into account at all. Instead it relies on IQroutes (where available) to take crowdsourced speeds for both ETA and routing.

 

[bednorem]

I've had the same frustration with rural routes in Texas. Out in the "country", our secondary and local roads have speed limits of 65 to 70 mph. TomTom's default is around 45 mph, which I assume is typical for more densely populated regions. This means that for long trips, it would always route us on Interstate highways, adding up to 50% more time to the trip.

With IQR, the routing has graduallly gotten better over the last 3 years, but it still comes up with some bizarre routing every now and then.

My favorite solution to this was one that was used several years ago by MS Streets and Trips. It would let you individually override the default speed limit for any of several classes of roads. This would be a trivial addition to the setup options in TomTom. I actually e-mailed this suggestion to TomTom, and got the standard "thank you for you input".

Oh, well. No PND is perfect yet, but the progress over the last 10 years has been amazing.