[Page Update] Junction_Style_Guide/Interchanges

[roadtechie]

Over the course of the past few months a committee comprised of mostly GLR editors has been working on a guide for the creation of a Diverging Diamond Interchange (DDI).

With the DDI becoming more and more popular we believe this would be an excellent addition to the Junction Style Guide/Interchanges wazeopedia page.

Special thanks to Bill473, ehepner1977, falco_sparverius, fbisurveillancevan21, phoenixhawke, GizmoGuy411, jbayes, Kartografer, RonRover, and TerryPurdue.

Last, but not least many thanks to PesachZ and Sketch for their feedback on early drafts.

https://wazeopedia.waze.com/wiki/USA/User:Roadtechie/Junction_Style_Guide/Interchanges

[OhioStMusicMan]

1. Regarding elevations - I think the elevation should be adjusted between the inner ramps and not the outer ramps.

2. Should there be any specification about what the voice prompt(s) should be when the ramps meet the surface street?

[subs5]

Looks good.

Here is a more complicated DDI since one entrance has a left turn lane split…

Don’t think has to be in the general write up, but can mention that other configurations exist.

[herrchin]

It may be worth special mention to check all geometry and resulting turn instructions for all connected ramps. Lots of variation can occur for DDIs based on number of lanes, Waze road type, and pavement layout. One size does not fit all, and just drawing to the natural pavement may not result in the appropriate TTS. Maybe also explicitly say to not TIO at the crossovers, as some may be tempted to put in a keep-left.

[jm6087]

Looks real good, thanks for the work on this.

[subs5]

Some states have done some good animation clips that might be decent links to add as additional information.

[subs5]

@herrchin

Maybe also explicitly say to not TIO at the crossovers, as some may be tempted to put in a keep-left.

For people who have not driven on a DDI before it is very foreign and a keep left could be appropriate so that they don’t try to go counterflow especially at night. Not sure why it has to be “explicitly” stated.

[jm6087]

@subs5

@herrchin

Maybe also explicitly say to not TIO at the crossovers, as some may be tempted to put in a keep-left.

For people who have not driven on a DDI before it is very foreign and a keep left could be appropriate so that they don’t try to go counterflow especially at night. Not sure why it has to be “explicitly” stated.

I think the issue with a keep left TIO would be the fact that the design of the DDI has you facing the direction you are going, so in reality you are not keeping left, you are going straight. If a keep left is given, it may encourage someone to make a left turn instead.

[subs5]

I have done the two DDIs in Virginia and did not use Keep Left on the crossovers. So far no URs so probably not needed. Just not sure that we have to state to not use them.

I would think that having a reminder to put in the “Exit Left” TIO would be appropriate since some still think if angle is correct then get it for left exiting ramps.

[roadtechie]

We considered TIOs but determined in the typical case they are not needed. Obviously reconsider with each specific example, as no two are identical.

[sketch]

Looks great. I am not sure about the bit about elevations. First, generally I agree with this:

@OhioStMusicMan

1. Regarding elevations - I think the elevation should be adjusted between the inner ramps and not the outer ramps.

Though it depends on the situation locally.

The note about elevations seems to imply that the elevation of the segments between the ramps should be the one changed in any situation, even if the DDI is ground level and the freeway is elevated. This is misleading to me, as in such a case the DDI should be ground level and the freeway should be +1 (or whatever is necessary) per the “map to reality” standard in the US wiki article.

[roadtechie]

@sketch

Looks great. I am not sure about the bit about elevations. First, generally I agree with this:

@OhioStMusicMan

1. Regarding elevations - I think the elevation should be adjusted between the inner ramps and not the outer ramps.

Though it depends on the situation locally.

The note about elevations seems to imply that the elevation of the segments between the ramps should be the one changed in any situation, even if the DDI is ground level and the freeway is elevated. This is misleading to me, as in such a case the DDI should be ground level and the freeway should be +1 (or whatever is necessary) per the “map to reality” standard in the US wiki article.

Due to the concern over elevations that section has been removed. Elevation guidance should follow the standards the region/state already has in place.

[roadtechie]

Thank you for the feedback everyone. The proposed changes have been made. https://wazeopedia.waze.com/wiki/USA/Junction_Style_Guide/Interchanges#Diverging_diamond_interchange_.28DDI.29

[Nagamasa]

Never driven on a DDI, but would there be any benefit (if at all possible) to wrap a JB through it, given:

• the likely very different signal timing for on-ramp/off-ramp traffic versus through traffic
• DDI configuration is relatively standard
• high amount of nodes for very few conflict points

[jm6087]

@Nagamasa

Never driven on a DDI, but would there be any benefit (if at all possible) to wrap a JB through it, given:

• the likely very different signal timing for on-ramp/off-ramp traffic versus through traffic
• DDI configuration is relatively standard
• high amount of nodes for very few conflict points

IMHO, I don’t think a JB would really benefit the interchange. The TRs are pretty straightforward.

[Nagamasa]

Oh no the turn restrictions, but for consecutive segment timing.