Best GPS traffic service: XM or FM/TMC?

Reader Martin L. emailed me the other day, asking about GPS traffic services, among other things. I couldn't really tell him which service,  XM NavTraffic or TMC - the Traffic Message Channel (FM) was better, so I suggested he check out the GpsPasSion traffic forum. Martin came across this thread, comparing XM vs. FM traffic services for GPS receivers. Though the sample is small, it seems pretty clear that XM NavTraffic is the hands-down winner.

But this led to another issue. Martin lives in NYC - urban canyon land, so he wants a GPS with the SiRFstar III chipset. Well, here's the weird part. Garmin hasn't paired these technologies yet. SiRFstar III receivers use FM/TMC, while XM receivers use the older chipsets. But that is about to change.

The Garmin zumo 550, which I wrote about here, marries these two features. Unfortunately, it's designed for a motorcycle. But if you read the fine print, Garmin says it includes both a "motorcycle mount and automotive mount (with integrated speaker) for riding or driving." When originally announced, the zumo was supposed to be available in October, but the product page says fourth quarter.

Now how good the zumo is for automobile use is anybody's guess, but I'm sure a number of people are hoping that Garmin adds this feature set to more new products, and/or that TMC cleans up its act!

Comments

[Jim D]

Navteq provides the data for the XM traffic service delivered via XM's signal. Navteq also provides the traffic data for Magellan delivered via TMC over CBS radio stations. Total Traffic Network a Clear Channel company provides the data for the Garmins delivered via TMC over Clear Channel radio stations.

TMC (traffic message channel) merely describes an FM subcarrier designed for delivering traffic information and does not have any bearing on the information sent over it.

To compare the traffic capabilities between the Streetpilots and the Zumo is also comparing two different traffic reporting systems, Navteq and Clear Channel along with different information transport systems FM vs satellite.

A better comparison to determine if the delivery system is at fault would be to use a Magellan with traffic capability along side a gps using XM traffic.

[Rich Owings]

Excellent point Jim. I'm glad you clarified the difference between the data provider and the carrier.

Hey, now we just need a volunteer, in an urban area, with two appropriate units to test! I'm hoping to get some traffic units to test in the near future, but I doubt that they'll overlap.

[Tom McCallum]

I live in Atlanta, where gridlock traffic is one of the worst in the county and wanted a nav system with traffic updates. I bought a Cobra navone 4000, and was very disappointed. The database or onboard maps were not very good. The FM traffic worked about 30 percent of the time.
I bought this system from Costco because of there return policy, that's a good thing because this system is going back. After reading some of these postings it looks like the way to go is the XM or satellite system. So let's give the Garman 2820 a try. Can't beat the reviews.

[Rich]

Hi Tom,

The traffic area is one that is rapidly evolving, and I continue to see differences of opinion on which provider is best. Good luck with the Garmin 2820. Please let us know how it goes. I'm sure your experience would benefit many readers here.