Monday, April 9, 2007

The Interstate 375 Overpass Fire

Wednesday evening, 28 March 2007.

The flyover ramp from Interstate 275 southbound to Interstate 375 eastbound was quiet. The evening commute wrapped up a few hours ago.

Until sometime before 11 PM: A gasoline tanker trailer on its way to Sarasota to deliver fuel to the many convenience stores there did not make it to its destinations - instead, tragedy unfolded as the driver of the tanker trailer, thinking he may have still been on Interstate 275 headed south, exited onto Interstate 375 eastbound. Not knowing the fact that the driver was on a 50 mph ramp instead of the 65 mph highway, the tanker burst into flames as the driver tried to negotiate the near-sharp flyover ramp.

The tragic result was that the driver of the tanker truck passed away and a large fire ensued on the flyover ramp. As the flyover ramp goes over a City of St. Petersburg maintenance yard, several pieces of equipment owned by the City were lost as the gasoline from the tanker truck rained down from the overpass above.

The next morning engineers from the Florida DOT surveyed the damage to the overpass as a result of the tanker fire. It was concluded that a span of the overpass needed to be replaced as the concrete damaged in the fire was in no condition to let traffic back on.


Looking at the entrance to Interstate 375 eastbound from Interstate 275 southbound the morning after, 29 March 2007

With the Honda Grand Prix of St. Petersburg being held the next day and the season home opener of the Tampa Bay Devil Rays a week away at Tropicana Field (plus the so many commuters that regularly use this ramp) how do you manage to get by with one less exit ramp into downtown St. Petersburg? Interstate 375's cousin to the south, Interstate 175, provided the answer along with a few alternate routes into downtown St. Petersburg. From what I understand, these events got off without a hitch traffic wise.

However, I believe several factors contributed to this tragic event. I wrote the following letter to the St. Petersburg Times in response to an article published on Saturday, 31 March 2007:

When this section of Interstate 275 was built in 1977 I believe the exit onto Interstate 375 (Exit 23A) should have been constructed as a right hand exit with access to 5th Avenue North. However, when the interstate was built with the left exit onto Interstate 375 the signage was well marked with advisories and warnings regarding the left exit and the reduced speed limit to 50 mph.

As a result of numerous sign replacement projects including the most recent one in conjunction with a concrete pavement rehabilitation project a while ago the left exit advisory signage - including the yellow "exit only" panel on the bottom of the sign - was replaced with nothing more than a diagrammatic sign without any mention of a left exit advisory. Any warning of a left exit onto Interstate 375 (or its counterpart, Interstate 175) from Interstate 275 today is nothing more than a little post mounted "Exit 50 mph" sign on the left side. I agree, once you are on that ramp onto Interstate 375 it's too late.

There is a similarity between the accident on Interstate 375 at Interstate 275 and the charter bus accident on Interstate 75 in Atlanta: Both exits have minimally marked left exit advisories. Perhaps if the left exit advisories were better signed these tragedies may have been averted.

Yes, the Interstate 375 ramp should have been constructed as a right exit. Having to exit from the left lane is confusing, yet sometimes dangerous. However, the left exit design was planned for in the very first place as Interstate 375 was supposed to continue west to the beaches as an east-west beach expressway but that idea was nixed long ago. The only remnant of this idea is a ghost ramp which can be seen on the ramp from westbound Interstate 375 to southbound Interstate 275.

Yes, the signage for Interstate 375 east from Interstate 275 south (Exit 23A) does not provide for any left exit warning. Back in 1977 when this section of Interstate 275 opened it had signage for Interstate 375 east complete with an "Exit Only" panel for the two left exit lanes as well as side mounted signage warning motorists of the 50 mph speed advisory for the ramp. Thirty years and a few sign replacement projects later the signage was replaced by two diagrammatic overheads and the overhead at the point of exit no longer has an "Exit Only" panel attached to the bottom. The only warning signage that exists today is the small side mounted 50 mph advisory signage on the left side of the exit ramp.

It should be interesting to note that at one point the MUTCD - or the Manual of Uniform Traffic Control Devices, the book that defines the standards for road signs in the United States - did call for the use of the "Exit Only" panel when you have lanes departing from the mainline highway as part of the exit. The MUTCD was revised a few years ago to eliminate the "Exit Only" panel requirement when the lanes departing from the mainline interstate highway go to another interstate highway such as the junction of Interstate 275 and Interstate 375. I believe the "Exit Only" panel requirement should have been left in place as eve though you are transitioning from one interstate highway to another, you have exited from one interstate highway to begin with.

I believe the Florida DOT should upgrade the signage for both Interstate 375 and Interstate 175 (Exit 23A and Exit 22) from Interstate 275 south stating the fact that these exits are left lane exits and placing better warning signage such as the tipping truck graphic warning sign found in Tampa at Exit 39 (FL 60) from Interstate 275 southbound.

As for the overpass from southbound Interstate 275 to eastbound Interstate 375, work is progressing at a steady pace to get the overpass sections replaced and the overpass open to traffic again around 1 May 2007. Having this overpass open would be a relief for commuters as well as those headed to Tropicana Field as a good alternate route.

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