New Feature Request - no U turns

[Martin Gregor]

Could there be a button do disallow U-turns. The situation has been discussed before, I think. When I decide to take a different route than the one calculated by Osmand, I get the commands to make a U-turn ASAP, sometimes it can go for miles. WIth this button, Osmand would be force to calculate a new (different) route
Thank you

[Peter B]

instead of vorbidding u-turn I would prefer a function to "recalculate route",
Peter

[sympa]

Is the problem that Osmand does not recalculate, or is the problem that turning around is the best possible solution?

In any case it doesn't hurt to equate a 'random' U-turn with about 800 meters of distance. It depends on how busy and safe the road is, but sometimes it may not be possible to turn at all without hindering, being unsafe, or it is just plainly forbidden.

If the route calculation were really fast there could even be an announcement like this: "continue straight or please turn around to save 5 minutes". That would make a very very nice addition when leaving for example a crowded highway; the user would immediately receive an update how long the detour will be. The following steps in the route will then be announced in a similar manner: "turn left in 500 meters or turn around to save 2 minutes".

[Martin Gregor]

When I was returning home from a place I visited, I decided to drive home through nice residential neighborhoods. Osmand relentlessly wanted me to make a U-turn to guide me to a local highway which I definitely wanted to avoid because of the rush hour. Only after couple of miles miles it gave up.

[Suranga]

Pin your "nice residential neighborhoods" as waypoints of your route. Make sure you have them in correct order.

[Martin Gregor]

Hi Suranga, I understand your suggestion but I just decided on the spur of the moment to turn there.  Same thing happened the other day, when I went to a shopping center some 30 miles away. On the way home, I knew the shortest route, yet OSM for perhaps 5 miles used every 'opportunity' to ask me to make a U turn. It is not a big deal but with all the programming feats, I don't think it should be a problem to introduce a simple command "no u-turns". Thanks for responding. I think I am not the only one who had an issue with false U-turns.

I had another post some months ago, when I went to see doctor to Washington DC. some 35 miles from home. It was during the rush hour so left and u-turns were not allowed. So where I was supposed to turn left, I could not, at the next intersection, where OSM requested to U-turn ASAP, there was, again , no U-turn sign during the rush hour. It was the same for a couple of miles. On some intersections, U-turn prohibitions are not even mapped. I do lot of mapping and when I remember some of those prohibitions I map them when I get home, but it is beyond my (and I guess many other mappers) to add rush hour restrictions (it is pretty much impossible to try to write down the exact time restrictions when you are behind the wheel), so as a result, they are not mapped.

So from my standpoint a simple option, no U-turns would solve a couple of headaches one might encounter.
Martin

[Suranga]

Hi Martin,

I now realize how important the feature is. I have seen this option in MapFactor. I have not used the app for navigation since it was not stable in my device.

By the way, where do you suggest to include the selection/option for "No U-turn". Should it be option to enable in Navigation menu, or a navigation screen button. Keeping it on navigation screen would be a waste since it is not a button with regular use.

I suggest to make it a "Pop-up icon" appear only during "Please make a U-turn" directive.

Hope we'll get this feature in future updates.

Suranga

[Martin Gregor]

Hi Suranga: A pop up icon is a great idea. When the first U-turn appear, just tap on "no U-turns" and the problem is solved. And after you close the program, a dialog asking if you want to keep no u-turn as a default or only for this trip.

Martin

[hans.marc...@googlemail.com]

Hello!

But I was wondering: If you tell the routing engine not to use U-Turns, how will it realize that you also do not want to turn right, right, right and then left? Or even slightly mor complicated alternatives to a U-Turn?

In your first Use-case you don't want U-turns, because you know a better route. On the second, you are not allowed to. So you tell the routing engine, that it is not allowed to use U-turns. It will guide you right, right, right and then left, back to the route. The second use-Case would have been satisfied by the U-Turn-restriction, the first one not. 

But I was thinking: If you are at a given place X, following the route. When you are asked to U-Turn, the dialog could ask you if you want to take a different route. Something like avoiding the next 1, 2, 5, 15 or 25 miles. Let's say, you choose 5 miles. You could then tell the routing engine, that the roads on the original routing, for the next 5 miles should be avoided. It would force the routing engine to search for a new route. This would be interesting in events of an unexpected road block (accident and so on). 

But if you know the best way, than a different behavior could be for you. Something like a temporary suspending routing for X miles. But remember: For the routing engine, it's way is the best, and not yours. And that is fine for people that do not know that area like you do. 

For the U-Turns during rush hour: They should get mapped. And even if they did not, you could turn by "right, right, right, left turns". Then you would be back on the routing. No navigation software is perfect.... I know of no device, that does it without mistakes and that is OK also. In other countries you have different restrictions also based on the rush hour. How should those get addressed? 

Please note, I understand your point, but I don't know, if disabling the U-Turn is the correct way to do that. In one case you would start optimizing the routing engine for people that actually do not need guidance. But because that routing-engines is by no way trivial you could be making it worse for other routes, you don't know. Perhaps in other countries, where roads are mapped differently. I am also not sure (second case), if a navigation app should be as good as local people are. In my eyes a route is valid, as long as it takes you from start to the end, within a reasonable amount of time.

Hans

[Martin Gregor]

Hi Hans: Lot of good and valid points. One can find arguments for both. I don't know how complicated programming is but a combination of a your idea (take a different route) and pop up icon could be a compromise. Let's say I get a command to make a U-turn, so I tap the pop-up icon, make no u-turns,  which gives the instruction to OSM both, to cancel U-turn commands and, at the same, requests to figure out a new route. In this case it would not ask me to make left turns again and again at following intersections in an attempt to guide me back to the originally calculated route. Who knows how this would turn out, I just think one would have more options. I don;t think this is a 'frivolous' option

Like many others car drivers, I guess, I use the map most of the time in the area where I live, to do errands, to visit a doctor, or get an idea to visit a shop in an unfamiliar part of the city (suburb) etc so I still think it would be useful, or something along those lines. I just get these commands very often and often they last for several miles.

In therms of mapping them, as I mentioned, I spend lot of time (under my other id slover98) mapping, and in my area there are still tons of buildings and roads missing, so to map the roads and buildings are my first priority and frankly, I don't know how to map no u-turns etc without actually observing them personally, and it would take lot of time. I tried to find traffic maps of my county that would potentially show these, but there is nothing. So realistically, one cannot expect that these would be mapped any time soon.

Thank you for responding,
Martin

[Suranga]

Hi Friends,

Thanks Hans, I agree with your points. "Avoid next X miles/km" is truly an original approach.

I tested MapFactor with "No U-Turn" this morning.

1. I set the destination away from my office and started navigation.

2. In about 5 seconds after I turned opposite direction, route recalculated towards the direction of movement.  Note that this was a two-way road (single roadway) and we drive on the left side of the road (right hand driving).

3. As Hans predicted correct, It kept on showing me to turn right, right, right, left to get me back on the same road towards the other direction (obviously I ignored all instructions).

4. Then, when I entered dual roadway (two one-way roads in parallel), it kept on instructing me to take "sharp right turn", which is in fact the U-turn, at every possible point. When I look at those points on Openstreetmap; two one way roads are linked using short road sections. Therefore, these points are in fact two right turns.

So, I believe, this is the kind of functionality we could expect from simple "No U-turn" function.

Regards.

Suranga

[Martin Gregor]

Hi Suranga: That's a great test! And Hans was right, impressive. Looks like something more sophisticated is needed (no U turn + calculate a different route). It would seem that based on the test results the no U turn option is not feasible, but, on the other hand it does prove that a more 'intelligent' behavior is needed from OSM. By going in the opposite direction OSM should be able to figure out soon that the user does NOT want to take the original route.

Thanks again for testing,
Martin

[sympa]

The problem is that it is not easy to guess the intent of the driver. He may have taken an exit to take a short break, for example. Or there may be a huge traffic jam ahead that must be avoided.

TomTom solves this with a button "Obstruction at XXX meters" (for which I would prefer "Avond next XXX meters" by the way). They also have "Calculate alternative" - probably making the segments of the original route less optimal, and thus fining alternative solutions that avoid the original road segments a little.

Another way might be to show a pop-up "calculate different route" when deviation from the intended route is detected - which would avoid the original route, possibly by lowering the estimated speed on those segments.

TomTom also has a "Recalculate original" route function which would also be needed - maybe the alternative route isn't working out.

[Suranga]

Hi Martin,

In fact, no U turn is feasible when driving on a two-way (single roadway with both direction traffic), as I only get instruction “when possible, please make a u turn” only when I am on such roads (and in my case, those are the majority of roads I drive on). This option is helpful for some other requirements also, for example larger vehicles which find it impossible to make a u turn.

Hi Sympa,

What you suggest seems more practical in terms of developing routing algorithms. Thank you. 

[Peter B]

Solutions like "avoid xx meters" will be complicated in programming, so the chance of realizing is low.

What about trying to get an easy solution? The chance of an easy solution to get realized is better.

If the u-turn message/symbol accurs, then tapping on it should activate a recalculation. This could help for the most situations, I hope.
Peter