Hi all,I love my street pilot(Garmin 340)being a over the road truck driver it saves me hours a week plotting my routes,the main reason I bought the pilot,was to keep ne off roads with low under passes,13,6 is the height of my trailer,since owning my pilot,it has taken me to one under pass that was 13,ft.When I bought the pilot I specifically,ask if this was possible,I was told to put the device on truck mode which I did,I think all this does is give you more warning time before a turn.Any Thoughts??


The truck navigation mode simply attempts to keep you on major roads. The map database does not currently have the overpass height information in it.

On this site, there is a current POI project for low clearances. Take a look at this page. Keep in mind as the page indicates that it is a work in progress.


I have also heard that the

I have also heard that the truck mode does nothing at all, just there for the future when (if) they make anything specifically for trucks, such as low clearance bridges.

But I have also heard the same as what MM just said too.

Charley - Nuvi 350 - Bel STI Driver - Cobra 29 w/ wilson 1000 - AIM: asianfire -

Question about the Low Clearance file

In the file "underpass clearance.csv"

Line 15 which reads:

seems to be a railroad underpass in Newark, Delaware. I am wondering if this underpass is not specifically for trains and cars and trucks actually use the over-pass on Casho Mill Road.

Maybe I am not understanding something?

Garmin Truck Mode

This was an answer from a Garmin afficianado regarding truck mode:

The truck and/or bus routing options, when available, tries to keep you out of residential areas at greater costs (in time or distance) than when using car/motorcycle.
These routing options will also try to avoid sharp turns (more than 90°), when possible.

Finally, they'll clip the top speed used on the different roads, to make a more realistic ETA calculation.

There's no height (tunnels, bridges) or weight informaton on the maps, so no concern to such things can be taken.