Hi Steve,
We know that short arc are problematic, but not exactly why. There are a few possibilities.
1. The routing arcs have a length field, when the arc length is less than 4.9m (in our implementation) this is stored as 0. Perhaps zero is bad and using 1 instead would work.
2. Perhaps the nodes must have different Garmin coordinates. This would imply a minimum separation of 2.3 (or less depending on direction and latitude).
3. I believe that boundary nodes between two maps are considered connected if they are up to 2 (or 3, I forget) garmin units apart. Perhaps this is true in general and routing will jump to unconnected roads if nodes on nearby roads are too close.
A lot of maybes :-( I have one more: I think Garmin also changes the algorithmn with new firmware (one version broke routing completely on my Oregon 450t, don't remember exactly which one it was)
(I thought of that last in relation to removeShortArcs removing complete ways - how did no one notice? Well perhaps because very small gaps can be jumped).
The small way is removed, but the gpx device will probably still route you through it (if my last description of the algo is correct) I am more concerned that it may remove a way with highway=steps and connect the nodes of two big street directly instead. Gerd