Highway 40 Re-opening: Final Predictions

Well, the wait is over. St. Louis’s two year traffic nightmare is about to come to an end.

What’s that? It wasn’t really that bad? Oh, I guess you’re right, but you wouldn’t have known that from reading this blog – dead since the original shutdown began in January of 2008. The original predictions of mayhem (including some of my own) thankfully didn’t come true. Yet, as the highway plans to re-open, I thought it would be a good time to embarrass myself some more by issuing some final predictions.

Highway 40 traffic will flow more smoothly

There are a lot of good improvements accompanying the Highway 40 reconstruction, most notably on the mainline highway itself. The ramp from eastbound 40 to northbound I-170 has been a welcome relief for West Country drivers headed to Clayton or Washington University. Fewer — yet longer — on-ramps will eliminate congestion. Back in 2007, I predicted better traffic for Highway 40, and today’s Post-Dispatch article confirms it. I look forward to seeing it.

So, the mainline highway design is the winner, but what about the crossing arterials?

Brentwood and Hanley intersections will suffer

A big reason for the anticipated improved traffic flow at Highway 40 and I-170 is the merging of the Brentwood and Hanley exits into one. From either direction, there’s just one off-ramp and one on-ramp for both Brentwood and Hanley combined.

This is great for flow on Highway 40, but it also increases the amount of traffic going through the lights at Brentwood and Hanley. Exiting eastbound 40 for Hanley? You’ll have to stop first at Brentwood. On Hanley wanting to get to westbound 40? Again, plan on a stop at Brentwood. Same story if you flip eastbound/westbound and Hanley/Brentwood.

See the plans in all their details on MoDOT’s site.

Fortunately, Brentwood will have less traffic due to the ramp from eastbound 40 to northbound I-170. Yet, all told, I think you’ll see more traffic and probably more congestion at the Brentwood and Hanley intersections. Keep an eye here over the next few weeks — first to witness all the confusion and complaints over the merged exits, and then to see if traffic flows well at these intersections.

Lindbergh intersection at risk for gridlock

Lindbergh Hwy 40 interchangeYou might think that the Lindbergh intersection is old news. After all, it’s been open nearly a year without any significant issues. However, traffic exiting Highway 40 to Lindbergh has been lower than it will be after the re-opening, and I’m a little worried.

As you know, the new interchange at Lindbergh introduced a new stoplight for the Single Point Urban Interchange (SPUI). This light is awfully close to the Lindbergh-Clayton intersection (see image), and — prior to construction — southbound Lindbergh traffic would routinely back up under the Highway 40 overpass. If that were to happen with the new interchange, it could block traffic from getting through the interchange at all, causing gridlock. Additionally, those drivers going from eastbound Highway 40 to southbound Lindbergh have no merge lane, just a yield sign. Backed up traffic on Lindbergh will block these drivers from getting off the highway.

Careful timing of these lights will go a long way toward avoiding gridlock, but I wonder if these close intersections can handle it.

So Long

Well, that’s all my predictions for now, and likely my last post for this blog. I’ll leave the site up for another couple months, but I suspect by February, the Highway 40/I-64 closure will be a distant memory.

This entry was posted on Sunday, December 6th, 2009 at 10:13 pm and is filed under Brentwood, Hanley, Lindbergh, Predictions. You can follow any responses to this entry through the RSS 2.0 feed. You can leave a response, or trackback from your own site.

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