TMC rubbish data or weak signal?

[sgreenbank]

I live and mainly drive in East Sussex and have had a Garmin 215T for quite a few months.

Some places the traffic data is lost which is apparently normal. But locally it seems to be working as using traffic search I get a list of problems - which seems to have a max of 16 incidents.

1) However firstly local traffic problems A22,A21,A27,A23 rarely seem to appear on the unit even when there are significant problems. In fact my usual nearest incidents/roadworks are almost always inside the M25.

2) Many problems that are fairly predictable don't even appear eg. rush hour Friday evening various sections of the M25 or A3 Hindhead. I sit listening to radio and hear for hours of incidents that are on-going eg. last Friday J10-J18 M25 and other places too. My Nuvi never mentioned it.

3) My Nuvi flags roadworks/incident affecting an A road in one particular direction - the radio reports long delays both directions due to one-way working.

4) Some incidents seem to turn up and stay on there for months. Now obviously if it were roadworks this could be true - however I checked one of them myself and the junction in question had no roadworks.

Since locally my Nuvi will re-acquire consistent information if I turn it on and off I have always assumed that it is receiving the correct info. However there just doesn't seem to be a lot of it. eg. Friday July 17 evening rush hour it was reporting 12-16 problems from upto and over 200 miles away. Apparently only one Motorway had a problem and that was over 200 miles away. This is frankly just not believable - as confirmed via the local radio reports.

Is the supplied info really this bad or do I have some other problem?

[bazzam111]

At least yours works my 775t ('allegedly' with lifetime traffic) has none

[tsdinos]

The answer is probably BOTH weak signal and rubbish data!
I have a nuvi 760 I'm driving every day the M27 from Portsmouth to Romsey at my workplace and it seems that is working occasionaly on the M27 but it is NOT TO BE TRUSTED!!!!
There is a a big delay from when the actual event happened until it gets displayed on the GPS. It will then re-route you to A nd B roads which has no traffic information for them and it assumes that everything works fine, when in reality there might be more delay on them than staying on the M27.
I once followed a detour and I bitterly regret it, as it turned out that the M27 has been cleared from the traffic long ago, and I had to follow some narrow B roads that run through villages, thus delaying my journey at double the time.
I think the best way to avoid the traffic is still to physically listen to the radio and ignore the GPS data. It will definately take a few years for the TMC to be considered as a reliable working system

[Gardela]

The problem also lies with Garmin TMC software, which doesn't pick up some of the slower moving traffic, at least in Scotland. Mind you, it used to, so I don't know why they don't just swich back to the previous version (anyone here know how to do it?).

I was in touch with Garmin about that in March/May and they're still working on an update. Maybe we should all drop them a line to speed up the process, because I'm really getting fed up. The guy I've been in touch is called Jonathan - a very pleasant and helpful chap. I can't provide his surname and Garmin email address here for obvious reasons (spam etc.).

[sgreenbank]

Thanks for the replys.

The idea that I am suffering from a weak signal seems odd because the listed items seem to regularly include the same roadworks and if the signal was weak I would expect a random selection of the current problems.

I too have noticed the Scotttish problem although its generally not a problem in the SE!

How many incidents can the Garmin flag at once I don't think I have ever seen more than 16?

Has anyone seen a problem posted for both directions of travel? Even on Motorways there is often a big queue in both directions for a problem on only one of the carriageways. Yet if my Garmin flags an incident at all it never seems to inclde both directions.

[bradders2]

I had Trafficmaster factory installed in a previous car, a 1998 Vauxhall Vectra. It appeared to work quite well. I now use TMC with a nuvi760. Although the green signal light on the lighter adaptor is often illuminated, I rarely pick up much traffic data here in the North West. It would seem that we haven't made much progress over the past decade

Chris B
_________________
Chris B

Garmin nuvi 2595LMT
Garmin nuvi 760T
Memory Map Adventurer 2800

[Allan_whoops]

I have an old AA Vodafone Roadwatch trafficmaster receiver which I use. It is by far the most reliable in terms of warning what is going on up to 3 junctions/15 miles ahead. The paid for TMC system on garmin comes a close second. The standard free TMC is worse than useless. The first two are, I believe, directly linked by radio to the sensor system whereas the latter uses FM radio transmissions.

[sgreenbank]

I have updated the software and the traffic news is much better in that I sometimes see problems on local roads and Scotland is back. Counting the messages these seem to exceed 40 at times. I'm still not convinced its all that accurate as known rush hour problem spots don't seem to get flagged all that often.

Also I still haven't spotted the rubber necking effect that I see so often. eg. big crash on the motorway often causes big queue in both directions - quite often worse on the carriage way that is clear! However this seems only to ever indicate a problem in one direction - even when there are one-way traffic lights on major single carriageway roads.

Is the Garmin or the broadcast system not capable of showing a problem in both directions at more or less the same location?

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