This off-and-on isn't difficult at all

[skbun]

Hey, all.

Any thoughts on how to prevent the off-and-on you'll see in this livemap link? There's no crossover or tie I can think of that will reasonably do it.

To be honest, I'm not even certain it should be disallowed. There's often a big backup on I-5 N around this curve, and although convoluted, it does get around it, often, and since it's hitting at least one city street, it's technically not 'just' an off-and-on.

http://www.waze.com/livemap/?zoom=12&la ... g=54301579

[khaytsus]

If it's a real problem, you could work here:

https://www.waze.com/editor/?lon=-122.4 ... s=54304608

And make sure that this ONLY connects where it's supposed to, and of course make sure other roads work as well. I did this in Louisville on one section that persistently had users going off onto a side ramp and then back onto the interstate. I made it so the ramps ONLY went where they were supposed to, and not back to the interstate, with a bit of extra connection ramps and a parallel path or so.

Here's how I did it there, maybe a similar approach will work for you. Be careful, and trace the paths to make sure you get it right!

https://www.waze.com/editor/?lon=-85.72 ... s=69318623

[skbun]

If it's a real problem, you could work here:

https://www.waze.com/editor/?lon=-122.4 ... s=54304608

And make sure that this ONLY connects where it's supposed to, and of course make sure other roads work as well. I did this in Louisville on one section that persistently had users going off onto a side ramp and then back onto the interstate. I made it so the ramps ONLY went where they were supposed to, and not back to the interstate, with a bit of extra connection ramps and a parallel path or so.

Here's how I did it there, maybe a similar approach will work for you. Be careful, and trace the paths to make sure you get it right!

https://www.waze.com/editor/?lon=-85.72 ... s=69318623

Oyyyye. Well. I think it's a done deal. Feel free to check my work if you're curious! I had to do two close-in bowties on the slip roads, two long lengths of parallel road, and found a place where the Interstate itself had a turn restriction. FUN! (And it only took about an hour and a half!) It's locked down at (3), has no turn restrictions, and should look fairly transparent to a client user - while preventing off and ons with parking lot segments.

I can't really prevent the going all the way down I-705 and back again (the cyan route shown earlier) if Waze REALLY decides that's what it has to do, but there's only so much I _can_ do. The purple routing should be dead and gone, and it appears 'direct on I-5' was borked by a turn restriction in the first place.

[khaytsus]

https://www.waze.com/editor/?lon=-122.4 ... s=70478149

What in the world is this segment? Might recheck this right here, something odd going on.

Not sure this is really connected?

https://www.waze.com/editor/?lon=-122.4 ... TTTFTTTTFT

I didn't trace it out yet, just looking at the basics of what you did.

[AlanOfTheBerg]

There's a few overlapping ramp segments here (to the west) which seem to be the antithesis of simplified mapping. Why can't they be combined instead of being stacked? Does it have to do with which lane you are coming in on?

[khaytsus]

There's a few overlapping ramp segments here (to the west) which seem to be the antithesis of simplified mapping. Why can't they be combined instead of being stacked? Does it have to do with which lane you are coming in on?

Alan,

From my suggestion, the attempt was to prevent Waze from routing users to the slip road then back onto the interstate. I had a case of this in Louisivlle, KY that I kept getting UR's on and I made some adjustments. I had to make some parallel stuff but not as extensively as the one he made.

He hasn't responded yet, so I think I'm going to take a shot at some of the stuff I saw and go over it, as I think it's a bit broken right now, I just had no time to look into it more yesterday.

I've edited, I think it's right, but there's no (sane) way to completely isolate everything here. I really hate these sliproad configurations, they're difficult to fix with additional roads and connectors... Is there ever a valid case of Freeway I5 to ramp to ramp2 to rampN to Freeway I5 is valid? Two different freeways, yes.

[CBenson]

I'm curious about the advantages of this configuration? Why the parking lot segment rather than the turn restriction?

[khaytsus]

I'm curious about the advantages of this configuration? Why the parking lot segment rather than the turn restriction?

I missed that one entirely. I'd think he meant to use Ramp there but I'd have to trace it out.

Haven't heard back from the OP, I wonder if he's still working on this.

[CBenson]

If you use a ramp and a turn restriction. Couldn't you then simplify the whole thing by eliminating the four segments and bringing all four junction nodes together as one? I'm not seeing the point of the four segments except to make the one a parking lot segment. And I don't really understand the advantage of the parking lot segment.

[skbun]

I'm curious about the advantages of this configuration? Why the parking lot segment rather than the turn restriction?

Yeah, it IS intentional - both the design and the presence of the parking lot road, and there are definitely advantages to this over the turn restriction. A lot of this comes from experience, and I typically create these on cloverleafs, or 'freeways with off and on slip roads'.

With this bowtie crossover...
* The two parallel roads are so close together, at the 2m zoom, that on a client, it just looks like 'one slip road'. Completely transparent to a client user.
* The only nav advice Waze will ever give a person coming from I-5 N is to take the left ramp of the two, and in the context of this exit, it's 'straight ahead'. (I'll have to show a maps.google.com link to explain, but I've driven it. See http://goo.gl/maps/IFqjs ). The placement of the bowtie is right in front of the actual road split so the TTS shows the right distance. The parking lot road is there to assure that there is not an off-and-on nav suggestion (going back to I-5), but if someone DOES do it, it won't generate a UR either.
* A person coming from S 38th St will get two options, with the correct TTS: either 'stay to the left, to SR-16...', or 'stay to the right, to I-5 N / I-705 N...', thus the careful placing of the fork and the angles.
* If we do this 'the other way' with a single segment and turn restriction: when enough clever drivers do an off-and-on on one of these slip roads, I've seen from experience that inexperienced editors will go to such a junction with a UR, see 'Restricted turn might be allowed', and invariably will allow the turn - meaning 'allow the off and on' - because it's in theory possible, and we're back to an off and on issue again, so it goes in circles.

When I do THIS with a ramp, especially if locked down, this is generally the end of it. Everything works properly, and we don't get turn allow URs, 'incorrect junction' errors because of bad TTS instructions, or circular edits. I did one of these on a cloverleaf on I-405 in August as a testbed, and never saw a UR generated by problems with the bowtie.

(Apologies for how long it took to get back to you all! I hadn't subscribed the topic, so I just plain missed replies after the initial couple.)