I don't like the idea of leaving the DDI elements stop-controlled (especially the crossover in the upper left of the photo). Seems like that would cause a lot of accidents, since it's an unfamiliar design concept anyway.
Keep in mind that the dominant movements at this interchange are essentially following US 93 (NB 15/93 > NB 93 and SB 93 > SB 15/93). These movements are free flowing.
The other dominant movement will likely be between Las Vegas and the Republic Services landfill. The northbound movement is a free flow, while the the southbound has one stop.
I'm also concerned with the unregulated crosstraffic at the first intersection (Apex Crossing?) which looks to be a major accident waiting to happen. I wonder how long it will be before both are signaled.
I'm not understanding which spot you're talking about. Every intersection or crossing has a stop or yield control.
NB stop makes sense so that traffic coming off the interstate doesn't queue back onto the ramp. That one I'm on board with. I would also call this an English interchange more than a DDI.
The way this illustration depicts the stop signs is indeed confusing; an initial look shows the sign aimed directly at traffic coming from NB I-15/US 93 on to the continuation of NB 93. However, the signs as shown seem to be always on the right side of the affected lane(s), which would mean that, contrary to my original observation, the sign is actually on the lane coming from SB US 93 to both NB I-15 and the frontage road on the east side of that freeway -- and that the direct NB US 93 move is the nonstop direction through the DDI apex, which would essentially obviate any queueing onto the NB 15>NB 93 ramp. Not the best example of illustration; the STOP octagon should be shown with the lettering at an approximately correct angle facing the oncoming SB 93 traffic intending to turn north on I-15 or continue on to the frontage road. Took a bit of staring at the illustration/map -- and "defocusing" on the sign direction depicted but rather the placement. Still think stop signs are a "stop-gap" (no pun intended) measure, and signals won't be too far off!
Yeah, the stop/yield sign illustrations are a bit misleading, as it seems they are always oriented to face the "camera" as opposed to being oriented relative to the animated traffic that it would apply to. But note that the graphics depict each stop location with a stop line marked on the pavement. The video animation clearly shows how vehicles will stop or be free flow when you watch it, as well as the narration indicates where movements will stop or be free flow.
Keep in mind they're building this in anticipation of a potential industrial complex going in along US 93. Buildout of this center is still a ways off, and will be incrementally piecemeal–NDOT is attempting to get ahead of it. Current traffic counts (2016 data) along US 93 just north of the interchange is about 3000 AADT. So as to signals, I don't think signalization is incredibly imminent at the moment but I can potentially see the crossover needing signalization well down the line as the industrial complexes come on line.