Washington's First DDI coming soon

[Great Lakes Roads]

WSDOT is considering a diverging diamond interchange at Interstate 5 and State Route 510 in Lacey.  This project is scheduled to begin in the 2018 construction season.

Video:
https://www.youtube.com/watch?v=55gTGYOas6k

[compdude787]

Cool! I was not aware that WSDOT was planning on putting in a DDI there. It seems like a good place, I suppose.

[Bruce]

I don't really like the DDI coming to this state, but that spot is as good as any, with the somewhat miserable pedestrian traffic.

[jakeroot]

I've never seen a visual with a person jogging. Pretty cool animations as usual, WSDOT (although I know the animation isn't done in-house).

Anyways, I think this would be a great place for a DDI. There is a lot of turning traffic at this interchange. Big areas for shopping both north and south. One thing that I've noticed is that, coming south on I-5, the only way to access the shopping center in the NW quadrant of the interchange would be to turn right, then left at the roundabout. Which is fine, but it highlights one of the downsides of the DDI: no straight movements from the off-ramps.

[roadfro]

Anyways, I think this would be a great place for a DDI. There is a lot of turning traffic at this interchange. Big areas for shopping both north and south. One thing that I've noticed is that, coming south on I-5, the only way to access the shopping center in the NW quadrant of the interchange would be to turn right, then left at the roundabout. Which is fine, but it highlights one of the downsides of the DDI: no straight movements from the off-ramps.

Maybe I'm missing something...? As I look at a Google Map, there is nothing relevant in the NW quadrant of the interchange as of now (although it looks like something is planned between the interchange and the Cabela's a bit further west).

Even if there is something there now, is there access from the I-5 south onramp? That would be highly unusual, except if there was some kind of frontage road in place. Otherwise, there is not a reason for southbound I-5 traffic to exit and cross over the intersecting road to the onramp side that the DDI would inhibit.

[jakeroot]

Anyways, I think this would be a great place for a DDI. There is a lot of turning traffic at this interchange. Big areas for shopping both north and south. One thing that I've noticed is that, coming south on I-5, the only way to access the shopping center in the NW quadrant of the interchange would be to turn right, then left at the roundabout. Which is fine, but it highlights one of the downsides of the DDI: no straight movements from the off-ramps.

Maybe I'm missing something...? As I look at a Google Map, there is nothing relevant in the NW quadrant of the interchange as of now (although it looks like something is planned between the interchange and the Cabela's a bit further west).

Even if there is something there now, is there access from the I-5 south onramp? That would be highly unusual, except if there was some kind of frontage road in place. Otherwise, there is not a reason for southbound I-5 traffic to exit and cross over the intersecting road to the onramp side that the DDI would inhibit.

Perhaps I should have worded my comment differently . Indeed, there is nothing there at the moment, but according to the animation (and from just knowing the area -- I only live about twenty minutes away), there will be a shopping center in that corner, between Marvin Road and the Cabelas (the roundabout between the 5 and Britton Pkwy used to just be a circle with two legs, before they partly built the entry road for the shopping center).

If you look at the animation, you can see very briefly what appears to be a frontage road where the current 5-South on ramp is today, splitting towards the 5 or the shopping center. This design may be a way to eliminate some of the NB Marvin Road traffic that would be destined for said shopping center. One of the downsides of the DDI is poor signal progression, so removing some of the traffic from Marvin Road NB may be the best way to improve signal timing.

[Ron_VERG]

I've never seen a visual with a person jogging. Pretty cool animations as usual, WSDOT (although I know the animation isn't done in-house).

Actually the entire production was created in-house at WSDOT by VERG, the Visual Engineering Resource Group.

[jakeroot]

I've never seen a visual with a person jogging. Pretty cool animations as usual, WSDOT (although I know the animation isn't done in-house).

Actually the entire production was created in-house at WSDOT by VERG, the Visual Engineering Resource Group.

Sweet! You learn something every day. You wouldn't happen to work in the VERG division would you? 

[Ron_VERG]

Sweet! You learn something every day. You wouldn't happen to work in the VERG division would you? 

Yep, How'd you guess? :-)

I'm glad you like the video. It's always nice to hear that our work has been helpful in communicating complex ideas.

FWIW I've been doing design visualizations at WSDOT since 1998.