Diverging Diamond Interchange Simulation -- I70 in Washington, Westmoreland counties

This video depicts traffic movement through the Diverging Diamond Interchange (DDI) scheduled to be built at the Interstate 70 interchange with Route 19 in Washington County.

The DDI is a new type of interchange that is growing in popularity. The DDI can move traffic more efficiently compared to other interchange types.

The Pennsylvania Department of Transportation is in the process of implementing long term improvements to Interstate 70 in Washington and Westmoreland Counties. The purpose of the improvements is to increase safety and mobility. As part of the improvements, PennDOT will reconstruct I-70 between the junctions with I-79 adding a third lane in each direction and will improve the interchange with Route 19 (Murtland Avenue) in South Strabane Township, Washington County.

The current interchange at Route 19 is a substandard cloverleaf interchange that was constructed nearly 60 years ago. With the desire to minimize impacts and to account for the traffic on both I-70 and Route 19, a new interchange type was determined necessary.

[MyChannel-uvbm]

I like the idea of the DDI.  Of course, the most important change with this area is expanding I-70/79 to 3 lanes.  Only down side is that they're stopping at the west I-70/79 interchange; it should be 3 lanes all the way west to US 40/W Chestnut St.

[onyxe.s.]

you can do this same intersection without any traffic lights just use a tunnels where the roads cross no stopping no contact just a free running all the time

[MyChannel-uvbm]

One thought I did have. At other DDI-type implementations, what has the impact been to elderly drivers with this cross-over layout?

[CodeBleu]

I live 3 miles from this interchange. This is an innovative engineering marvel, but it's going to confuse the heck out of older drivers. While the traffic signals in place will help with merging, I'm afraid they just won't get it even with the signs telling you exactly where to go. This will avoid a lot of high speed highway accidents but low speed fender benders on 19 will be exponential at first.

[mrl]

The people who came up with this plan GREATLY underestimate the stupidity of the drivers here in PA. I see some wrong way driving and head-on collisions in the future.

[shdhd]

In the video from 1:50 to 2:30, the traffic stops at both lights. Is it possible to time the lights so that you do not have to stop at the second intersection? This may help traffic flow even better. With the extra stop, I'm not sure this would work any better than a roundabout at each side of the overpass.

[snickwad]

How long did it take to create the model and this animation? What software did you use? Thanks

[Mrwcginwash]

The only benefit I can see of this (Washington, PA) interchange is the elimination of the short and unsafe entrance/exit ramps to and from I-70.  But that isn't even mentioned here as a "benefit."  Other than that, adding more stoplights to an interchange where there is already a freely-flowing traffic movement (without stoplights) is simply making a more time-consuming and confusing situation.  Now, if there had already been traffic lights at this intersection, then this new interchange wouldn't be any different.  I travel this road everyday, multiple times a day and there are NEVER any issues with traffic not being able to freely flow through.  This could be overkill in terms of cost-benefit. So, in ending, I really don't see how this new design, along with the great expense of building it, is really going "improve" the flow of traffic.  That's just me.  Maybe the money used to construct this could go towards updating and upgrading a dilapidated bridge somewhere.  Heaven knows, there are certainly plenty of those.

[scottmoyer]

Traffic lights are a waste of EVERY resource. Maybe thats the point though.

[billhartsford]

Punch it! Don't let that Land Rover pass you!! lol

[melissaveltri]

This is amazing! Genius plan! Only concern is for the large amounts of morons on the road. Hope they figure it out and don't kill me

[Anschutzhammerlitoz]

How exactly does adding stoplights to an interchange without any stoplights "improve" matters? What specific flaws or shortcomings does the existing interchange have that will be alleviated by the new design, and are the existing shortcomings worse than the shortcomings that will arise from stopping traffic at the stoplights? Seems like nothing more than a colossal boondoggle and waste of taxpayer resources.

[mgtpa]

And they say this is an improvement...?? Multiple traffic signals and cross over traffic accidents waiting to happen. This interchange does nothing for safety as it only increases the risk of accidents due to red light runners. Nothing wrong with people not knowing how to yield to traffic.

[davislee]

Who came up with this monstrosity?? Accidents much??
Thumbs way down!!