I think this video explains the intersection more clearly:
http://www.youtube.com/watch?v=5aBxw-EJiLQ&feature=related

I drove on this last night, exiting hwy 40 — very very confusing! I expect there will be a lot of accidents there.

Really? How confusing could this be? There are plenty of other intersections just like this one in the St. Louis area. If Festus can figure it out I think CWE drivers will be fine.

If you can handle city driving and Kingshighway, you can handle a single point intersection. If you can’t, stay off the road.

Joe, I loved the youtube video. Not what I expected when I clicked but it was a welcome laugh.

So it’s identical to the I-170 interchange with St. Charles Rock Road, except that Kingshighway goes over I-64, not under it? Sounds easy enough.

Looks pretty basic. How complicated can this be? It looks the same as Highway 94 at I-70.

This identical to Big Bend & 141, which seems to work pretty well. I guess this style interchange is just in vogue right now.

Yep, same as 270 and Olive and Lindberg and 55. Both those intersections are WAY better than they used to be.

WHY do there always have to be naysayers like NightDriver? Stay home.

Sure it is easy to understand! However can someone explain why it was changed to this when we already a ramping which had no traffic lights? Seems like all we did was add to the confusion. The double ramps at each quadrant worked just fine.

I like how the yellow and red cars crash into each other in the upper right-hand corner as they attempt to enter the interstate during the 3rd cycle. Classic!

The 94/I-70 interchange in St. Charles is a great improvement, I expect this should be as well.

I live in Las Vegas (St. Louis born) and these intersections like this are popping up all over. Wierd the first time through but great after that. Not confusing and one less light to sit through (if you’re going straight).

That upper right-hand corner crash is a very typical crash as most drivers don’t realize that on the road “yield” is supposed to mean: stop if a car is present in your potential path, not pretty shaped sign I will coast past. I lived at an intersection with a “yield” sign only for east-west traffic and twice a summer there were accidents. The village wouldn’t put up a stop sign because there wasn’t enough traffic and cost involved. The officer we saw the most at the accident scene always laughed “and why didn’t you yield? You had a yield sign”

To answer Jack’s question, the problem with cloverleaf interchanges is called “weaving”. What I’m referring to here is having to weave in or out of traffic on the inner lanes that accomplish the equivalent of what would be a left turn if it weren’t a cloverleaf interchange.

The problem is, when you’ve got loads of vehicles wanting to make what would be the equivalent of a left turn during rush-hour, you’ve got an accident just waiting to happen because people must constantly weave into or out of traffic just to handle that mess. This is PRECISELY why cloverleaf interchanges are being phased out in medium-to-large urban areas and are being remade as single-point interchanges like this or, in the case of two freeways meeting, “cloverstacks” (where two cloverleafs on opposite sides of the interchange are replaced by flyover ramps), like you see at I-44 and I-270 or I-55, I-255, and I-270 in south county.

Besides, I don’t see why this causes confusion. After all, the St. Louis area already has plenty of interchanges like this, such as I-270 and Olive, 141 and Manchester, I-170 and Olive, and I-55 and 141, just to name a few.

This is very similar to the intersection at 270 and Olive. Much more efficient at moving traffic. Also it’s simple if you pay attention while you drive. If you chose to talk on your phone or put makeup on, then you might have issues.

It’s called a SPUI, Single Point Urban Interchange. They’re not complicated at all. They allow for opposing left turns all around, meaning one single traffic light only has three cycles. This will be what goes at 40/Hampton and 40/Lindbergh. The original 40 rebuild had SPUIs at 40/Big Bend, 40/Hanley and 40/Brentwood, but those were reduced to plain diamonds for cost concerns.

Other SPUIs in STL are at: 70 at 94, 70 at Belleau Creek Rd in O’Fallon, 170 at St. Charles Rock Road (St. Louis’s first SPUI, built 1983), 170 at Olive, 270 at Olive, 55 at Lindbergh, 55 at A in Festus, 141 at Manchester, 141 at Big Bend. Illinois has one at IL 255 at IL 111 in Bethalto. Several more are planned.

55 at 141 in Arnold is a modified SPUI.

This 40/Kingshighway SPUI is unique in that it’s the only one in St. Louis that has a dual right turn ramp from surface road to freeway. That being SB Kingshighway to WB 40. It is controlled by a traffic light, that is green when the main traffic light cycles Kingshighway on green and lefts from 40 on green. Obviously, it’s red when KW-to-40 lefts are green.

It amazes me how such a simple concept can be so confusing and controversial. St. Louis will never be confused as the “leading edge” when it comes to traffic control and road/highway design.

Data supports a very simple single point interchange such as the new kinshighway can support more cars per hour at a greatly reduced accident rate. They have been doing these across the country for years now.

Keep it simple. Copy what works in other, much larger cities and we will be fine. That is what we are doing with the entire Highway 40 project.

Fabulous! Wonderful! Easy to use interchange similar to others found in many places around the area.

The problem with that old cloverleaf at 40/Kingshighway was not only the conflicting weaving motions, but that the ramp from WB 40 to NB Kwy and the ramp from EB 40 to SB Kwy brought traffic too close to the next surface street stoplight, Barnes-Jewish Plaza and Oakland Ave, respectively.

This meant that, even though there was no stoplight along Kwy at 40, it meant that traffic would back up because the cars that wanted to exit 40 and go onto mainline Kwy had only a short distance to weave, likewise for Kwy traffic that wanted to turn right at either BJP or Oakland. Now, the Kwy mainline traffic has a stoplight, leaving the exiting traffic from 40 some room to queue in whatever lane it has to at the next light. Also Kwy mainline traffic has more room to do the same.

If you think a SPUI is complicated, wait until you see what MO DOT is going to put at 270 and Dorsett. They were going to do a SPUI, but settled on a Divergent Diamond Interchange (DDI). MO DOT seems to be the first DOT in the US to use them, they are common in Europe.

Basically, a DDI is where the street/road/boulevard that the highway has an intersection with, the street flip flops driving directions to ‘wrong way’ driving before the highway, then flips back after the highway. This means that you need two sets of traffic lights, but you can coordinate them to where, like a SPUI, there are only three cycles.

http://www.modot.org/stlouis/major_projects/I-270andDorsettInterchangeProject.htm

Trying to get on west bound 40 going north bound Kingshighway takes longer. The light stays green for only 5 seconds and when you get on the ramp, the sign tells you to merge left but the left lane ends and merges to the right. Did anyone with MODOT see this when the sign was posted?

I know cloverleafs are out of style now and it’s the rage to build new interchanges with some ridiculous acronym…but I felt the old cloverleaf worked just fine for KHwy.

My old commute took me south on KHwy to eastbound 40. There was no light - just get to the onramp in time and you were good.

The new light means that if you are pulling up to a yellow or fresh red, you WILL sit, for a long time.

The first time I used the ‘new’ interchange was northbound KHwy to westbound 40 - I swear the light was a good five minutes. Doesn’t sound that bad, but it’s another example of a scenario where before there was zero wait, just like getting on 40 east coming from the north.

Oh that and it now looks like ever other overpass in the metro area…why do they all have to be the same bland retro-art deco style?

I have to admit, the fascination over “single point interchanges” and the “oh my god, what is that…how cool” factor was cute for all of two and a half seconds. Really people, it’s an interchange. Single point interchanges have been around since ‘74. They are not hard to navigate and they move a ton of traffic. Fact. There will be two more of these by the time they’re done with Highway 40, and other than the ramps being a little more bowed, THEY WILL LOOK EXACTLY THE SAME. So get the excitement and confusion out of your systems…now. These aren’t popping up all over the place because they’re “all the rage,” they’re popping up because there are more people and they don’t want to spend an extra second in their car if they can avoid it. Single point interchanges and diverging diamonds fix this problem. They save you that second. Quick sid enote, DDI’s are not “common” in Europe. There are 3 in France last I checked and that’s it. Roundabouts, now those are interchanges that are common in Europe (and a real roundabout interchange looks NOTHING like what they’re putting at Spoede). Back to what I was saying. As others have mentioned, with how many people travel on the roads today, unless you are in a rural area, cloverleafs and parclos basically, well, they basically suck. They just don’t move traffic well. SPUI’s, DDI’s, and cloverstacks (although a full stack interchange would be best like at 40/270) to name a few fix this problem. Sure, I won’t appreciate the stoplight that will be underneath the Lindbergh bridge, but I will appreciate it FAR more than the death clover that used to be there. “No guts, no glory” should never be a phrase that enters an engineers mind when designing a freeway interchange.

I think the new Kingshighway-I64 interchange is positively elegant. Only one concern - will the entrance ramp from Kingshighway to I 64 West be widened at the end of the ramp? There are three lanes that have to merge into one lane. I see accidents down the road….