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Strange routing of u-turns

7 Jun 2017
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The routing can do strange things if you want to, say, go up a side road for a cafe stop then retrace your steps back to the main route. Here is an example - I was trying to plot a GPS route for an organised ride this coming weekend.

Here is the "direct" route for a small section - the points are on the route being used into & out of the village.

http://cycle.travel/map/journey/41977

If I try to add in the location of where the organisers have kindly laid on refreshments, at point 1, I get

http://cycle.travel/map/journey/41978

Instead of taking me straight back to the original route it takes me some way further on, then onto a footpath to another road, does a u-turn there, back along the footpath before finally putting me back on the road and past where I just stopped.

I've noticed previously that trying to add in a small detour the route will sometimes take me up to a mile further up the road before doing the turn-around. (It is usually at this sort of point I just use the cycle.travel route for reference & manually replot it on bikehike.co.uk to get a usable GPS file :-S)

Comments

Wed 7 Jun 2017, 15:45

The core routing engine (OSRM) disallows U-turns at via points by default. It is possible to get it to allow them, but doing that universally would make dragging the route harder in normal circumstances – much of the time it’d just create a ‘spur’.

So I guess the trick would be to add an option for “allow U-turns at this via point”. I’ll put it on the list – won’t be immediate but should be doable, and it dovetails with something else I'm planning to do.

Thu 8 Jun 2017, 20:29

That sounds great. Thanks!

Thu 24 Jun 2021, 19:08

Hi Richard, 

Just found this post from a few years ago, as I'm getting similar behaviour to this at an overnight stop on this route (https://cycle.travel/map/journey/234024), which attempts to route me initially away from the stop before looping back. 

It's not a big issue and maybe it isn't fixable, but would be a good fix, if possible.

Thanks, Ben.

Mon 28 Jun 2021, 17:12

Ah, yes. Ok, I’ve just tweaked it so that it will allow U-turns at overnight stops. If you force it to recalculate the route (just opening the elevation view will do that) then it should behave as you expect now.

(Looks like a great ride – I’ve always wanted to visit the Red Lion, but we usually pass on the river and there are no moorings!)

Tue 29 Jun 2021, 10:02

Great, thanks Richard. Hoping to do my first overnight cycling trip next month, heading over to meet the family next day in the Wye Valley for the weekend. 

Tue 29 Jun 2021, 21:33

I include quite a lot of U turns in my routes. My method is to add another via point close to the U turn via point, then select Go Direct to X, where X is the additional via point. Hope this makes sense, and that I've understood the issue correctly. Via points 3 and 4 in this route illustrate my point.

https://cycle.travel/map/journey/234979