>spring is here and more proof congestion is happening

Posted: 2011/04/01 in congestion, IDOT, MoDOT

>The St. Louis traffic twitter feed from Gateway Guide is still being monitored, but the last two weeks have been slow compared to recent weeks, with just a single stall in the middle of the night being reported and nothing else. This been somewhat a surprise, as the feeds were common from the previous six weeks starting from early February. However, with summer approaching and the road construction (and bridge inspections) starting up, the number of incidents and delays will start to increase again. Historically, off-peak and weekend closures during the spring and summer months have been common for the past two decades due to various patching, expansion joint repair, and inspection jobs. Don’t expect 2011 to be any different from previous years.

IDOT is planning on doing a weekend closure of 55/70 between 64 and 203 next weekend for bridge demolition, so expect heavier than normal traffic on April 9 and 10. (This is weather permitting, though.)

Speaking of heavy traffic, this still from the Gateway Guide 270/Riverview camera should prove the capacity issue during peak periods:
EW Gateway has put the Level of Service (LOS) at a D from Riverview to Route 3. This is surprising, as recent amounts of traffic during peak periods should suggest it should be an E or an F. Any incident that happens in this area puts traffic at an standstill, especially when it happens during peak periods. In the past month, there has been three incidents during peak periods that caused backups over 5 miles long, and only one of those incidents happened on the bridge. (The other two I briefly described them in earlier posts; and I posted the tweet on the third.) This document that also dates from 2004 that details some of the Metro-East needs also talks about capacity needs. Allegedly its a low priority compared to all the other needs on the list panned out since 2004. The new I-70 Mississippi River Bridge has some interesting points from this document:

  • Hourly capacity of the Chain of Rocks Bridge is approximately 3700 vehicles per hour.
  • Projected AADT for 2020 at 71,100 with westbound peak hour right at 3700 vehicles if the No Build plan was selected.

Keep in mind that document was made sometime in the 1990s. IDOT has since jacked up the projected AADT into the 80,000 range by 2025, and the new I-70 Bridge will only have 4 lanes instead of 8.

When IDOT starts putting out the orange barrels this year for the construction season, the off-peak congestion will obviously be there, and weekend hassles are not out of the question. Although IDOT is spending their time fixing up 55/70, don’t expect the 270 corridor to be let off the hook. Much of it is 45-46 years old and is already showing its age. The last hardcore work done on that corridor happened 13-15 years ago and most of it is showing signs of wear and tear. The bridge decks on the canal bridge is in terrible shape, the river bridge is going in that same direction, and the pavement is rough and loaded with potholes (even though much of it was done in 2008). Decades of heavy truck traffic (20% to 25% of all traffic in spots) has contributed to much of the deterioration, and it is common to find overweight trucks on the corridor just to avoid the weigh station on westbound 55/70 near Collinsville. Trucks also use the 270 corridor to Route 4 east of Troy just to bypass the weigh station on eastbound 64 near Shiloh. Route 4, despite being 2 lanes and hilly, has a high truck percent between 270 and 64. The truck AADT on 270 west of 255 never dips below 10,000 while the truck AADT on 55/70 west of 255 does not top 10,000 until the merge with 64. (The overall AADT on 270 w/0 255 is in the high 50s; while 55/70 w/0 255 stays in the high 40s until the merge with 64.)


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