technical/engineering "improvements"

[MikeMason]

so cynical.............

[Brassdad]

after waiting two or three years for some freeway interchange to be totally redone, have ANY of them ever been LESS congested and LESS accident-prone afterward?"

They get done?

[Teubonium]

bloke "... For instance, after waiting two or three years for some freeway interchange to be totally redone, have ANY of them ever been LESS congested and LESS accident-prone afterward?"

YES!! There are two outstanding examples here in the Denver area.
The I-25/I-70 intersection known as "The Mousetrap", and the I225/Parker Road interchange.

[tbn.al]

Living in Atlanta and being from Arkansas I am very familiar with the I240/I40 debacle. I go 72 now and cut across North of the airport. I miss the stupid I55 bridge exit every now and again but I just do a U-turn. How about the opposite. Here's one that had need to be fixed for years and hasn't been touched.

The Northside Drive HOV exit off I75 Southbound in Atlanta. It is also a left exit but the signage seems to indicate to those not familiar with the intersection that the far left lane is a continuation of the I75 HOV lane. You can easily get to the top of the ramp at 60 mph only to find a stop sign followed by a 30 foot drop. A college baseball team bus made that mistake recently and killed 7 people. Now maybe they will fix it. At least they could put up some big signs with unambiguous instructions or tire rumble strips. The paper said this was the 5th incident like this in 4 years. Duh!

[iiipopes]

Here in southwest Missouri, the tiny diamond/cloverleaf combination interchange that connects the main E-W route, I-44, with the main N-S route, US-65, has been obsolete for years. We're finally getting the latest idea in interchanges, dedicated lane "flyovers" which are supposed to help matters, and be the ultimate solution to interstate multi-lane limited access traffic flow. But wasn't that supposed to be the case with the diamond/cloverleaf combination interchange when it was first designed during the Eisenhour administration?

Scheduled completion: 2008. Will it be better? Stay tuned. We'll see....

[tbn.al]

Your locals will just stop at the top of the flyover to watch them putt out on number two green. Or is that 11. It's been a long time.

[tubatooter1940]

Pensacola, Florida has an I-10 project going on just like Boston's big dig. The construction area is spreading and the going increasingly more hazardous.

[Mark]

For instance, after waiting two or three years for some freeway interchange to be totally redone, have ANY of them ever been LESS congested and LESS accident-prone afterward?"

Hopefully Rick won't read this thread. It's all the Aggies' fault!

[Chuck(G)]

It's them federal dollars.

The city fathers here couldn't resist the lure of a bunch of "use it or lose it" taxpayer dollars to give us a dedicated right-of-way bus system that has to offer free rides to get its ridership. Saves all of 6 minutes over standard bus:



Since the transit district is made up of appointed, not elected, trustees, they went ahead with the project even after several surveys overwhelmingly came up with the question "Why?"

I guess the answer is "Because it's free"

Someone observed that for the same money, the city could have furnished limousine rides for the ridership for the next 30 years.

[Rick F]

The Northside Drive HOV exit off I75 Southbound in Atlanta. It is also a left exit but the signage seems to indicate to those not familiar with the intersection that the far left lane is a continuation of the I75 HOV lane. You can easily get to the top of the ramp at 60 mph only to find a stop sign followed by a 30 foot drop. A college baseball team bus made that mistake recently and killed 7 people. Now maybe they will fix it. At least they could put up some big signs with unambiguous instructions or tire rumble strips. The paper said this was the 5th incident like this in 4 years. Duh!

That was really sad news about Bluffton University charter bus accident.

About 3 years ago I got caught in the HOV lane on I-75—but going North. It was somewhere south of the I-85 interchange if I remember right. All of a sudden I was exiting I-75. Thankgoodness it was daylight and I could see my mistake. They do need to improve the signs there.

[Rick Denney]

For instance, after waiting two or three years for some freeway interchange to be totally redone, have ANY of them ever been LESS congested and LESS accident-prone afterward?"

Hopefully Rick won't read this thread. It's all the Aggies' fault!

Reading this thread is too much like work.

You can't compare a freeway interchange or widening project after an improvement to the same interchange before the improvement, because the traffic demand has increased during the construction period. Compare the new interchange congestion to the congestion that would have been on the old one had it not been improved.

For example, everyone complains that I-696 (or is it 694--I forget) that runs across the north suburbs of Detroit was congested from the moment it opened. But they don't seem to notice that many of the surface streets in that corridor are no longer nearly as congested as they once were. If capacity exceeds demand, there won't be any congestion.

Congestion is HIGHLY sensitive to demand (1), and an improvement of even 10 or 20% can make a huge difference. You may still see congestion, but you'll be processing many more cars.

But consider that every freeway interchange has to be planned for about 30 years because of all the do-gooders who think it ruins something they like, or cynics who think it can't cure what they hate. Then, you have to have an environmental impact statement, which takes anywhere from a year to forever, and then you can get a Record of Decision. Once you have that, you can start designing it, but only within the conceptual design approved in the EIS. EVERYONE gets input into the design. It's a horse designed by a committee, and many on the committee are people Bloke admires, if he admires anybody on this earth.

Most of what makes interchanges work well make them expensive.

The reason cloverleafs were popular in the 50's is because they are cheap and don't consume too much right of way. They knew how to design better interchanges then, but the public wasn't willing to foot the bill. The structures in a cloverleaf are short, and structures are the most expensive part. But they have a maximum capacity for interchanging traffic of 1500 vehicles per hour in any one interchanging movement. I can do better with a well-timed diamond interchange traffic signal with dual left turns, not that anyone but a handful of us really know how to do that.

Four-level directional interchanges can be made with right-exiting ramps and two lanes on the ramps with higher demand. But the result are large and expensive structures. The best freeway interchange I've ever seen is US-59 North and I-610 North Loop Freeway in Houston. It's a dual-ramp four-level directional interchange with two-lane ramps, and that interchange will move 700,000 cars a day in all movements. The US-59 South/I-610 West Loop Freeway interchange, built in 1967, was a single-ramp four-level directional interchange and it routinely carried the highest or second-highest amount of traffic of any interchange in the world for two crossing freeways, at least for the first 25 years of its existance. It's big. The highest bridge in the stack was the highest bridge over land in the world when it was built; pretty impressive considering that where it was built is dead flat. The one on the other end of 59 will carry more. It was designed in the late 70's.

Both were designed by Aggies, and those Aggies were one reason that Texas, in the 70's and 80's, had the best roadway system in the world. But Aggies have designed some real losers, too, though often as a result of those influences by people who think they are experts on freeway design but who would never let those Aggie civil engineers tell them how to do THEIR jobs.

This is too much like work.

Rick "working on a freeway interchange project in Philadelphia that is projected to cost $600 million" Denney

(1) Denney, Jr., Richard W. P.E., Freeway Management and Communications chapter, Handbook of Transportation Engineering, Myer Kutz, editor. McGraw Hill, New York: 2004.

[iiipopes]

Your locals will just stop at the top of the flyover to watch them putt out on number two green. Or is that 11. It's been a long time.

That's the interchange a couple of miles to the west, for Glenstone Avenue, an even tinier and more cramped diamond/cloverleaf, which you actually have to slow down as you round the curves instead of being able to accelerate as you need to to merge safely, which it's actually more entertaining to watch the dodge cars at rush hour than it is to watch the hackers at the public golf course you're referring to.

I travel to the Kansas City area for various reasons semi-regularly, and I will say that their rebuild of I-70, I-435 and US-71 has been, in my view, successful, combined with the outer roads of MO-7 and MO-13 to get true 4-lane highway from Springfield to Kansas City. A generation ago, it used to take 4 hours plus to get from Springfield to downtown Kansas City, now it takes 2 1/2.

[Mark]

The US-59 South/I-610 West Loop Freeway interchange... The highest bridge in the stack was the highest bridge over land in the world when it was built; pretty impressive considering that where it was built is dead flat.

It is very high. In fact, my older sister refuses to drive over it beacause she finds it too scary. I think it's the best view from inside your car for at least 100 miles in any direction.

Both were designed by Aggies, and those Aggies were one reason that Texas, in the 70's and 80's, had the best roadway system in the world.

You understand that being from Texas and having attended a university other than A&M, I am required by law to make Aggie jokes.

[Rick Denney]

You understand that being from Texas and having attended a university other than A&M, I am required by law to make Aggie jokes.

Be careful, or I'll sic Dr. Jones on you.

Rick "who has the means to defend himself" Denney

[tbn.al]

That was really sad news about Bluffton University charter bus accident.

About 3 years ago I got caught in the HOV lane on I-75—but going North. It was somewhere south of the I-85 interchange if I remember right. All of a sudden I was exiting I-75. Thankgoodness it was daylight and I could see my mistake. They do need to improve the signs there.

In the paper this morning the Georgia DOT has reiterated it's stand that the exit ramp conforms to all federal codes and was not the cause of the bus accident. However, just to be on the safe side they have decided to improve the ramp with larger signs, more visibile striping and raised roadbed reflectors across the entire lane to act as rumble strips. The ramp was closed for repair at 9:00 AM this morning and the work should be completed on Thursday. It's a good thing, but it won't help those poor Bluffton kids or their families. This really should have been done last year when it killed that lady from Dalton.

[Rick F]

This really should have been done last year when it killed that lady from Dalton.

Having worked for the FAA more than 30 years, it's sad to say that the U.S. Govt many times "reacts" rather than "act".

[Rick Denney]

In the paper this morning the Georgia DOT has reiterated it's stand that the exit ramp conforms to all federal codes and was not the cause of the bus accident. However, just to be on the safe side they have decided to improve the ramp with larger signs, more visibile striping and raised roadbed reflectors across the entire lane to act as rumble strips. The ramp was closed for repair at 9:00 AM this morning and the work should be completed on Thursday. It's a good thing, but it won't help those poor Bluffton kids or their families. This really should have been done last year when it killed that lady from Dalton.

In my experience, the sorts of things they did are unlikely to have made any difference in the accident rate or in any particular accident that got a lot of publicity. It's the stuff they do to placate grandstanding politicians (and the media and citizen groups who goad them).

Rumble strips? Was the bus driver asleep? What effect is introducing an intentional loss of traction in the stopping zone supposed to accomplish? Bigger signs? Is there any real reason to believe that the signs are too small? Were the markings the reason why the driver had the accident? I'm unfamiliar with the ramp in question, but there are indeed guidelines for signs and markings on freeways, and they are defined in the Manual on Uniform Traffic Control Devices. I'm quite sure the signs and marking in question complied with those standards, because the feds wouldn't have approved the use of federal funds for construction if they didn't (okay, that's a theoretical statement). But the biggest sign and boldest marking can still be ignored or misread.

I'm not saying there isn't room for improvement on traffic control devices and I've seen my share of bad freeway guide signing and marking. But the usual public reaction is for more and bigger signs. We already have forests of signs at every intersection--so many that people don't even see them any more. Go to any given busy intersections, especially at a divided highway, and take a look. Count the signs. I think you'll be surprised.

One accident, however tragic, does not define a trend. Neither do two. Chance bad luck plays such a big role in accidents, and the contributors are so numerous and varied, that it is nearly impossible even for experts to link cause and effect. I've testified in a number of tort liability cases and found that even the smartest people have very poor ability to read an accident report, understand the traffic controls, and draw a reasonable conclusion about what happened. Remember, accidents are rare--usually less than one accident per million vehicle miles. Rare things are by nature hard to understand and predict.

Everyone who has a driver's license is an arm-chair traffic engineer. It's easy to diagnose something after the fact, whether or not the diagnosis is correct, because it will never be tested. If people forget about the recent accidents before the next one occurs, then they will think the rumble strips actually worked, without any hope of testing whether the same result would have happened had nothing been done at all.

And traffic engineers are so often pulled this way and that by grandstanding politicians and concerned-but-misguided citizens that they spend all their time applying such window dressing to locations that merely seem unsafe. The places that seem unsafe often don't have a high accident rate, because the apparent danger is obvious and drivers take more care. It's the places that seem safe but have hidden faults that cause problems. But those don't ever get much attention, and those programs are the first to be cut and the last to be the pet program of supportive politicians. After all, everyone hates traffic congestion and blame the traffic engineers for it, not they and their fellow motorists for filling up the roadway (or for their do-gooder neighbors whose concern for right-of-way acquisition, aesthetic sensibilities, or political agenda prevented the roadway from being designed properly).

If a traffic engineer spends time really trying to identify the problem locations, the bosses will complain that their bitching is not being responded to. And if the traffic engineer spends time responding to the bitching, there's much less time available to be more systematic. Welcome to the real world. Only in the wealthier suburban communities is there hope of enough resources to do both. Bloke's complaint about Memphis is that the politicians are spending money on crap (e.g., sports stadia) instead of on basic functions of government. I include the transportation network as a basic function. Bloke might not, but our quality of life depends in no small measure on that comprehensive network of relatively good highways.

So, the statement "they should have..." is usually a presumptive reaction. You have no idea what they did. They may very well have analyzed the intersection and determined that only digging it up and rebuilding it would do any real good (this time ignoring the constraints placed on them by politicians and do-gooders the first time around). Maybe that location fell way down on the list of high-accident locations, and was just the unlucky spot where a high-profile tragedy occurred. My bet is that the main fault was a bus driver not paying attention or driving too fast for the conditions, or similar actions by a driver in front of the bus.

Rick "been there; done that" Denney

[Rick Denney]

This really should have been done last year when it killed that lady from Dalton.

Having worked for the FAA more than 30 years, it's sad to say that the U.S. Govt many times "reacts" rather than "act".

That's because they have been beaten down for trying to act without the public outcry that forces the reaction. And politicians and citizens and advocacy groups are often doing the beating.

Rick "summing up for those unwilling to read my lengthy homily" Denney

[tbn.al]

Is there any real reason to believe that the signs are too small? Were the markings the reason why the driver had the accident? I'm unfamiliar with the ramp in question

Yes. Yes. and I am very familiar with the ramp in question.

1. It is a left exiting ramp, which is backwards from what we expect.
2. It is an HOV lane which has different signage requirements. The signs are all much smaller than normal, non-reflective and are black letters on a white background rather than the normal interstate green.
3. The last sign you see before the split says merely HOV with a split arrow. No mention of exit. You passed the exit sign a quarter mile before. There is a normal size stop ahead sign, but it is halfway up a short straight ramp. By the time you see it there is barely time to stop if you are at highway speed.
4. I was on my way to the airport with my wife a couple of months ago and almost missed it myself, and I know the exit well. I was motoring along, bored and not paying attemtion as well as I should and found myself vering left. I, being familiar with the road, immediately corrected but I sure PO'd the guy behind me who had come up to fill the gap.
5. A local TV crew put up a camera and during one rush hour caught five or six people doing the same thing.

IMHO the politicians blew it long ago in this case. A friend of mine designed this exit, and 6 more just like it 40 years ago long before HOV lanes. He says it was political then. He begged the DOT not to use left exits, but because of right of way issues they made him do it anyway.

Sorry to get on a soap box Rick, but this deal really sucks!

[Rick F]

According to this link...

http://www.ajc.com/metro/content/metro/ ... ction.html

...there have been 82 accidents at this site. How many accidents need occur before they realize there's a problem? Way past time to do something I think.

There's a video showing some of the improvements being done here...
http://www.11alive.com/video/player.aspx?aid=68381&bw=