HD Live - Auto Express test

perussell · Frequent Visitor Joined: May 12, 2006 Posts: 292

Some interesting, but perhaps not surprising if we are being cynical, results from a comparison test in this week's Auto Express comparing SmartNav, a TT540Live, a Garmin with no traffic and a car with a factory installed satnav with TMC.

4 cars plotted an identical arrival point in Central London into each of one of the above satnavs and left together from the same point.

Seems the TMC car took 3 minutes longer even than the Garmin which had no traffic channel and that TT's much vaunted HD Live equipped car arrived only 1 minute ahead of the Garmin vehicle. (Total Journey time about 1 hr 22 mins) All 3 cars arrived at least 35 mins or so after the predicted arrival time on the sat nav at the outset.

Interestingly the SmartNav equipped car beat the TT by a clear 8 minutes and arrived within one minute of the estimated time of arrival given at departure.

OK, one test, not statistically significant but enough to make me question whether it is worth subscribing to Live services when my free subscription expires next week.

matthewj · Frequent Visitor Joined: Apr 03, 2006 Posts: 751

It is hard to see how that can be valid in any way really. If it was the same driver in each car, and they went at a controlled speed as a percentage of the speed limit at all times, then it would make sense. Otherwise it is too flawed to be useful. Is there a link to the details?

PaulB2005 · Posted: Thu Feb 05, 2009 11:12 am Post subject:

It would be interesting to know what time and day they did the test on. If at 3pm on a Sunday afternoon pretty pointless comparrison. If on a Monday at 8:30 am....

Also what's your thoughts on HD Traffic after 3 months use?

perussell · Frequent Visitor Joined: May 12, 2006 Posts: 292

As I said, not statistically significant, but each car's route did vary quite a bit depending upon what the sat nav offered - I guess the speed of each car was governed by the traffic they encountered and the diversions they were offered.

You might find something on the Auto Express website, sorry I don't have a link.

As far as the time was concerned it was 9 a.m. on a Monday.

My opinions of HD traffic are mixed, I am not a 'road warrior' so don't use it extensively but I have used it on a number of long distance trips. Performance appears variable, on several occasions I have arrived at a 'jam' only to find it doesn't exist, on other occasions I have been in congestion that was reported on one day but not another, and on occasions it has been very accurate.

I guess one of my favourite items is the ability to navigate to 'Google Search' i.e. my destination was not in the loaded POI but easily found using Google.

MrT · Posted: Thu Feb 05, 2009 11:42 am Post subject:

I find the best routing method is common sense with additional information supplied by the SatNav to aid with decisions. Seems many people route the opposite way around, expect too much from the SatNav and blame it when things go wrong.
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PaulB2005 · Posted: Thu Feb 05, 2009 11:45 am Post subject:

perussell · Frequent Visitor Joined: May 12, 2006 Posts: 292

Fair comment.

However the article states that the TT diverted on 5 occasions - so HD traffic was obviously pretty active still at that time of the morning and yet the car arrived only 1 minute earlier than the Garmin which just plotted a route without the benefit of traffic info and stuck with it

Seems like a lot of effort for not much return Laughing

matthewj · Frequent Visitor Joined: Apr 03, 2006 Posts: 751

I think it is also missing the point of satnav and HD traffic! The point of satnav is to guide you to your destination. The exact route doesn't matter. If you wanted to get the fastest possible route, you'd need local knowledge and to be sure that there weren't traffic delays. Oh, and that's the point of HD traffic - to tell you about exceptional traffic that will cost dearly. 5 mins delay isn't a problem, 105 mins delay is well worth knowing about. But of course most of the time there is no exceptional delay, and so you won't notice the benefit.

If you just want a routing test, you can do that sitting with all the satnavs on a desk and doing A-B planning, and working out where they go, averaging the stats etc.

Perhaps the real conclusion of this test is that satnav works well - they all got there without problem.

perussell · Frequent Visitor Joined: May 12, 2006 Posts: 292

Any sat nav, even a £60 one, should get you there - the point is how it does it!

TT promote the Live services on being able to divert you through to the fastest route avoiding the hold ups and using IQ routing to plot dynamically what should be the fastest route. In this case it saved 1 minute over a unit without any traffic info. My question is, is that worth the extra (significant) expense?

It was interesting to note that the SmartNav plotted a substantially different route from the other 3 units and was the clear winner.

I agree, you really want to be warned about the exceptional delays but these are often broadcast over the radio or via other avoidance gadgets such as my faithful Trafficmaster Freeway.

matthewj · Frequent Visitor Joined: Apr 03, 2006 Posts: 751

Andy_P · Posted: Thu Feb 05, 2009 12:58 pm Post subject:

DennisN · Posted: Thu Feb 05, 2009 1:14 pm Post subject:

For nearly £100 a year, I'll manage without the Live services, thank you. They should give me one to test - with three other units on the windscreen I expect I'd find what I already do now with three - negligible difference between the GO920T with RDS-TMC, GO720 with nothing and TTNav6 with map v675! Even with a long route giving slightly different distances, ETAs are so close as to allow me to choose the shortest of the three routes offered without detriment.
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If it tastes good - it's fattening.

Two of them are obesiting!!

MrT · Posted: Thu Feb 05, 2009 2:01 pm Post subject:

I agree with Dennis on this, there will be generally be little difference in arrival time and route.

I think HD traffic provides better information than the other traffic services (I have TT-GPRS, TMC and TrafficTV as well) and it is a personal judgement whether that is worth the additional cost. I do not have total confidence in it and still use TrafficTV on my mobile.

On the test above, the benefits of HD Traffic will not show through as whilst it covers more routes than other traffic systems, in the London there are so many streets close together that cannot be possibly covered, it cannot tell you the best route and if any of the rat runs are blocked.

HD does have advantages that I have experienced when leaving London heading North towards where I live, I can take many routes, the main being A1, A5, A41 & M1 and it is useful in determining which one (and the roads in between) has the least congestion at that moment.
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matthewj · Frequent Visitor Joined: Apr 03, 2006 Posts: 751

Guinness2702 · Regular Visitor Joined: Oct 23, 2008 Posts: 156

I'm not really expecting to get much out of traffic yet. Durning the motor racing season, I travel to circuits most weekends on a Friday night, after work. This is when I'm really expecting to get the benefits.

I do travel about 70 miles up the M1 on Fridays, usually, and on two occasions, my 540 has diverted me - once when part of the M1 was closed (i'dve struggled to find an alternative route without it - well, I would have looked at my map, but that would have meant stopping, finding a route, and memorising it, along with all turns). More recently, there was a jam up at Milton Keynes, and it diverted me off at the previous junction, along whatever road it is that runs parallel to the M1 - I could see the jam from where I was. I don't know how much it saved me, but before it diverted me, it claimed the delay was 28 min IIRC, and overall, it only took me about 15 min longer than I expected.

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