Don't rely on Garmin RV760 LTM GPS routes.

Rollnhome wrote:
There are many things I like about it, but I bought it for it's main function RV Routing. It does not do a good job of route planning. I have used Marine and Highway GPSs and always check the routes. Just saying with all the information and technology this should be a problem of the past. GPS has been around for what? 20+ years. The interstates and most roads have been around much longer. Much like Marco Polo we still need to rely on paper maps and commonsense.

The GPS satellites have been operational (full constellation of 24 birds) for 19 years, final launch of the first set was 1995.

Computerized automotive navigation, goes back to the mid 1980s using other location technologies, like radio direction finding and inertial guidance, but did not roll out to consumers until 1990 when inertial reference systems became stable enough for use in cars and costs could be brought down to a few thousand dollars. These functioned as moving map displays.

First GPS receivers for street use were shown at CES in 1998, but the modern "plan a route and talk me through it" technology did not show up until the GPS system was made available for public use in 2000, and navigation devices could incorporate a relatively inexpensive GPS receiver for location, rather than inertial systems. Actually for the talking part of it, I think more like 2002 with introduction of TomTom, followed quickly by the Nuvi with similar cost and capabilities. My earlier Street Pilot just beeped when it need to give me an instruction, which I had to read before it disappeared.

That is kind of a coincidence, as that is also when turn by turn navigation was finally introduced for pre-GPS automotive navigation systems. That first one (MASS) got locations data from wireless Internet connections, the way phones do now, but it worked only where an infrastructure was set up for it.

But the real problem with these devices, whether they use GPS or something else for location, is in the map databases. The maps have errors, permanently installed maps don't keep up with changing conditions, and we have expectations that don't match routing assumptions. On 101, the map database says the tunnel is too low for your RV, based on official information about clearances and the height information you supplied. You think it should route you that way, because you know you can make it through by keeping toward the center. That kind of information is too iffy for the routing program to deal with, when the official clearance info says the vehicle does not fit.