Last week we promised a discussion of manhole covers and why they often are out of level with the pavement around them. They might be higher, lower or tilted, but rarely flush except on the newest roads.
Mike Connors, St. Petersburg's maven of all things regarding streets and the stuff underneath, gave us a quick course in manhole engineering.
First off, manhole covers aren't what they used to be. Or maybe they're better than they used to be. For certain, they aren't as thick as they used to be.
When a contractor resurfaces a road, he is supposed to match up the manhole covers with the pavement. But because the new covers are not as thick as the old ones, it doesn't always work. And then, right from the get-go, you've got manholes that are lower than the pavement.
Another factor is that road pavement is crowned, and manhole covers are flat, which makes it difficult to get a perfect fit.
And because manholes come in a variety of sizes, it's also possible to get them mismatched with the frames below ground.
When a manhole is lower than the pavement, it can be elevated with rings, or collars. But these can move. If they depress on one side, they will protrude on the other, creating double trouble for those who drive over them.
"Manholes don't settle, but asphalt does after heavy traffic runs over it enough to compress it," Connors said. "Then you've got a manhole that might be on its original elevation, but that's now a quarter of an inch higher than the pavement."
Fixing the problems is an ongoing battle.
"There are literally tens of thousands of them out there," Connors said. "It's not just the city's manholes. There are manholes for stormwater and storm sewers, for water and reclaimed water, and vaults for electric, gas, phone lines and cable. All of them can have problems, and it's impossible to keep up."
Now you know.
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Ken Jacobs, traffic signal wizard and maven for Pinellas County, dropped some interesting information on me last week. If you recall, I had wondered why there were two traffic signals for one left-turn lane from eastbound Roosevelt Boulevard onto the northbound ramp to the Bayside Bridge.
It turns out, the same situation exists for the single left-turn lane from westbound Roosevelt onto southbound 49th Street N at the same intersection. Here's the reason, according to Ken:
"When the intersection was designed, the left-turn lanes were striped so that as you approach the stop bar the lane actually starts turning around the corner. The two signal heads were installed where one is directly in the middle of the lane, visible as you approach the intersection, and the other is further to the left so it is still visible to someone stopped at the stop bar.
"This condition is actually more pronounced for the west to southbound left-turn lane at the same intersection. If you have a chance to go in that direction, you will see a striped-out area that leads you to turn your vehicle as you approach the stop bar. At that time the second head is still within your view."
Cool beans. Great idea.
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There is confusion, including mine, over the intersection of First Street NE where it ends, more or less, in a T-intersection at Ninth Avenue N.
To continue on First Street south of Ninth, a driver has to make a quick left onto Ninth Avenue and then a quick right because the continuation of First Avenue is offset to the east.
When Ninth Avenue was a one-way street westbound, drivers making the jog found themselves going the wrong way against the one-way traffic.
So the city closed down the left lane of First Street where it comes into Ninth Avenue from the north. A sign warns motorists that their only option is a right turn onto Ninth from the right lane of First.
Now, however, Ninth Avenue is a two-way street, clearly marked as such. So the question is, can drivers now make a left onto Ninth from the left lane of southbound First, ignoring the stripes across the pavement that tell them not to proceed?
The official answer, for now, is that the jury remains out. The city has asked the neighborhood association if it would like to open up that left lane but has not yet received a response.
So, for the time being, the left lane of southbound First Street remains closed at Ninth Avenue, and all traffic must move into the right lane and make a right turn only.
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Traffic disruption warning:
The city of St. Petersburg has begun replacing a water main and other pipes on 10th Street S between 22nd Avenue and 26th Avenue. This is a four-week project, and during the construction period, one westbound lane of 22nd Avenue S will be closed.
This could result in some traffic delays, but not nearly as bad as they would be if the main broke and flooded the area. So be patient.
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Excuse me, I think you forgot something.
The paving equipment is gone. The orange cones have been picked up. And the folks in the orange vests have moved on to disrupt traffic elsewhere.
But along the newly paved U.S. 19 between Cove Cay and Park Boulevard there still are signs warning of uneven pavement and "Road Work Ahead."
As hard as we looked, we could find none of either. The only project that even resembled road work was beside the northbound lanes of 19, about even with 102nd Avenue N, where it appeared that some pipes were being laid along the edge of the road without any disruption whatsoever to traffic.
Hey, guys. Come get your signs. Surely you need them somewhere else.
- Dr. Delay can be reached by e-mail at docdelay@sptimes.com by fax at 727 893-8675 or by snail mail at 490 First Ave., S, St. Petersburg 33701.
