Same destination two routes

Any one way roads?

It may be trying to avoid traffic if your unit has that feature. Also, I have heard the GPS's will sometimes favor right hand turns over left hand turns.

My nuvi just hates the road I live on, it never routes me on this road it always routes me on other roads. Kinda like my road doesn't exists.

Different input parameters to the routing engine and the preferences it has internally and those you set will almost always cause the unit to pick a different route for the return.

Great circle route?

My Garmin sometimes route me through some small street and had me turn left on a busy main road..Why?

I have had strange routing instructions on some of my trips and almost always it is because of my Avoidances settings. Most often it is the difference between Quickest and Shortest Route. For example, my GPS wanted me to turn off the Interstate onto some local roads to save about 5 miles... with speed limits of 40 - 50 mph versus 70 mph! Other times I have made temporary changes (avoid freeways) but not switched back .

So check your Avoidance settings, because some of the exclusions can impose unforseen restrictions on the route the GPS offers!

Quite often freeway interchanges will make the difference in the way a return route is calculated - whether your route preferences are set for "Faster Time" OR "Shorter Distance". Keep in mind that either way, there will be a difference in distance AND time. Some states have extremely large cloverleafs, and even ONE second difference constitutes a "Faster Time".

The first time I visited a niece in Roanoke VA, my GPS sent me up a gravel lane in her neighborhood. She was out on her porch laughing. She said, "You are using a GPS instead of Dad's directions, aren't you."

I usually set my GPS to avoid unpaved roads. It seems to underestimate the additional time it takes to drive on a dirt road, so may send you on a bad road where it thinks you will save a minute, and you have to drive slow on a rutted potholed road, arriving later and stressed.

I've had a couple of cases where the road was or rqamp shows on the GPS, but it isn't recognized as being connected to the primary road.

In the case of the ramp, it didn't recognize it until I got 1/3 of the way around. If this sort of thing happens, it's natural that it will send you a different way.

If your destination(or conversly your origination point) is near an interstate it would affect the route if you chose "fastest" vs. "shortest"

heck, mine often comes up with different routes from just about the same place to the same destination. I can get one route from one point on the road, and a very different route from a second point on a road that connects to that road, even though the second route passes through the point where the nuvi calculates a different route. There can be no logical reason for this.