BaseCamp 4.4.2 Is Now Available

Well I agree with what you're saying as a general proposition. But I'm talking about 180 deg U-turns on a continuous 2-way street in the middle of a block. BC will plan these on a route despite that avoidance being checked, and my 550 will tell me to do that on the device if I deviate in such a way that it thinks that's the fastest way to the next waypoint or shaping point, again despite that avoidance being checked. It's happened many, many times.

It might depend upon what profile you're using. I assume you're using "Motorcycle".

As I said I leave it off since from my experience you can get routes that try and avoid looping under interstates (a very common thing to do in some US cities).

As I said before, this is no big deal. But it is an interesting theoretical discussion. Thinking about it some more and doing some testing, I think I see the nub of the problem.

In routing calculation, I’m thinking there is no circumstance where, absent a waypoint or shaping point to go to, a route would ever go down a road then make a planned U-turn and return on the same road. That would always add distance/time that could be avoided by turning at an appropriate sooner time. So in that case, BC would never plan a 180 deg. U-turn, and such a U-turn would never appear in the Route Directions, so it needs not be “avoided”.

In the case where there is a waypoint not at an intersection, BC seems to make the assumption that the stop is in a parking lot where you can turn around, because the directions will say that you’ve arrived at that point, and the next direction will be “Get on X St and drive north”, for example, even though you’ve approached the point from the north. This assumption may be right or wrong, but it does seem reasonable, since BC would have no way of knowing. So, again, there will NOT be a direction “make a U-turn”, and none to be avoided.

It seems to treat shaping points the same way. I think those are special and should be considered as “pass through this point and stay going in the same direction”, but that’s not the way it works.

Bottom line: in BC, there would really never be a U-turn that is planned by the routing algorithm, even though in the real world, in many cases it would require a U-turn if there is not a way to get off the road, turn around, and re-enter the road. So it makes me wonder why there is a U-turn avoidance available, I can’t think of any case where it would make a difference.

As for the device (I only have experience with the 550), when you deviate from the route, I think it could and should respect the U-turn avoidance setting and do a re-route without U-turns, but I’ve not seen this behavior, usually it just says “Make a U-turn”.

My thoughts, anyway…

So it makes me wonder why there is a U-turn avoidance available...

In every case I've seen a route try and avoid a u-turn it was, in reality the best/only way to go. That may not be true everywhere. For me the avoidance being enabled causes more problems than it (it is supposed to) solves.

I too run with mine disabled, and the only time I seem to get a 'u turn' is when I take a wrong turning. How it's supposed to work if enabled I'm not clear but 'avoid' to me isn't the same as 'never' ... so in certain circumstances I'd expect to get u turns even if I'd selected 'avoid'. That of course may not be how it's intended to work, it's just my interpretation. Perhaps the Basecamp team can let us know how it should work :confused:

Relative to the device, I understand both of you and agree. But to be clear, my comment quoted above about wondering why there is an avoidance for U-turns applied only to BC, not to the devices.

From my perspective, a significant use of my 550 is driving a 45 ft. motor coach, which cannot physically make a U-turn. So I would like/expect it to do a recalc if I'm off track and show me how to get back in the other direction without a U-turn, like going around a block. But this is sometimes not so simple, assuming that one can just make the next turn and get around a block can get one in big trouble when the road doesn't really connect back in the way you think it should.

From my perspective, a significant use of my 550 is driving a 45 ft. motor coach...

A zumo 550? That is intended for motorcycle use.

Have you tried the RV profile in BC?

A zumo 550? That is intended for motorcycle use.

Of course, I also use it on my motorcycle. But I can't afford having a 550 and a Dezl, so I use the 550 for both. Works very well.

Have you tried the RV profile in BC?

I can't say I've tried the RV profile, but I did try the truck profile for a while and found that too restrictive. We charter coaches end up going mostly where cars go anyway, so the normal driving profile seems to suit me best. Routes that I have done on the MC are MC profile, though.

Would anyone having the straight-line issue be willing to share with me your GPX file of that route? Also the map you are using would be helpful.

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Thank you!