jeffandnicole and I had this exchange on the thread on the Northeast board about speed limits in Pennsylvania increasing to 70 mph...
Quote from: jeffandnicole on May 03, 2016, 10:14:30 PM
Quote from: ixnay on May 03, 2016, 09:51:33 PM
The bridge over I-78 at exit 16 [Midway Road] in Bethel, PA was 13' 11" in August 2012 per GSV. I stayed at the Comfort Inn at that exit a couple of nights in the summer of 2010 and had "fun" watching the semis barely clear the overpass. I would not want have been atop a semi trailer, even laying down. This would've been a perfect place for an overhead "If you hit that sign, you will hit that bridge" sign.
ixnay
Since the legal height is 13' 6" and every truck would be built not to exceed that height, there should be no reason why that bridge would get hit.
Well...
...the overpass at Exit 17 (PA 419) also has a 13'11" clearance, and at Exit 19 (PA 183) there is a 13'10" clearance per GSV in August 2013*.
The Exit 16, 17, and 19 overpasses were all built in the 1958-59 period per uglybridges.com.
My question: Was it typical to build bridges so low on those first generation interstates post Ike's interstate highway act? (Too bad uglybridges doesn't give the bridges' clearances over what they're crossing.)
*GSV in August 2013 also showed the bridge at exit 13 (PA 501) as being under reconstruction, perhaps adding an inch or 2 to the clearance.
ixnay
There are projects underway or planned in the 12-year program to change those low clearances...the PA 501 bridge was rebuilt, and is higher than the old one. My guess is that most of those bridges, due to their age, need rebuilding anyway and will all be built higher.
Quote from: jemacedo9 on May 10, 2016, 08:19:00 AM
There are projects underway or planned in the 12-year program to change those low clearances...the PA 501 bridge was rebuilt, and is higher than the old one. My guess is that most of those bridges, due to their age, need rebuilding anyway and will all be built higher.
That doesn't answer my question, though I appreciate the info and apologize for whatever snark was evidenced, jemacedo. Why were they built so low in the first place? Was that typical for the era?
ixnay
Could be as simple as the standards at the time. Maximum height is 13' 6"? Then a 13' 7" overpass will do! In fact, there are numerous standards that have changed over time from when interstate highways were first built. In general terms, the actual travel lanes haven't changed at all - most of the changes have to do with safety, such as wider shoulders, better guardrails, larger medians, brighter lines, etc.
This is probably true of highway overpasses also.
I would imagine that most of the newer overpasses, if built from scratch, would allow for 14' 6" to 16' feet of clearance room, minimum. If it's a simple roadbed reconstruction, they will probably try to lower the roadway to squeeze a few extra inches if they can't get to the standard minimums. Minimums out west tend to be a bit higher, especially as their oversized/overheight permit equipment tends to be larger.
When the GSP's Interchanges 9, 10 & 11 were reconstructed, you can go thru their online documents to see that the class of roadway requires different overpass heights. Using examples, the overpass for the local roadway at Interchange 10 may have required a bridge height one foot greater than the local roadway at Interchange 11. Why does it matter? I'm sure the additional 1 foot becomes many hundreds of thousands of dollars, affecting bridge heights, right of way requirements, utilities, water drainage and runoff requirements, etc, etc.
I recall a story, possibly apocryphal, about the construction of the Erie Canal. The builders did all the easy stretches first and used up all their budget in the process.
Then they went back to the legislature and noted they had finished whatever % of the whole project and just needed an additional doodle to finish up things. And the money was forthcoming.
I might think the early years of interstate construction might have similarly focused on the 'easy parts' and the more of the system that was completed, the greater impetus to finish off the gaps (hello Wallace Idaho).
And maybe a corollary to this principal, there might have been a little thinking that a given stretch of early interstate might have seen some scrimping on expenses, the understanding being there might not be money to do it right, but there would always be money to do it over. (and another opportunity for the contractor to bid on a profitable job)
And jog my memory here, do I recall correctly on I-80 west of Des Moines there were some overpasses that were raised twice?
If so, there is a corollary to a corollary . . .
Along the same lines.. I remember all the interstate bridges and overpasses in Florida had no shoulders.. Just asking for bottlenecks and complete shutdowns from a stalled vehicle or accident
Seriously raised bridges (https://www.google.com/maps/@31.5497723,-83.533997,3a,75y,346.32h,86.45t/data=!3m6!1e1!3m4!1sMCmrl-eOFx3Y0WLodxW-Ew!2e0!7i13312!8i6656) on I-75 in southern Georgia. Construction on these started very early after the Interstate System came into being, like 1956 or '57.
Quote from: jeffandnicole on May 10, 2016, 09:49:31 AMWhen the GSP's Interchanges 9, 10 & 11 were reconstructed, you can go thru their online documents to see that the class of roadway requires different overpass heights. Using examples, the overpass for the local roadway at Interchange 10 may have required a bridge height one foot greater than the local roadway at Interchange 11. Why does it matter? I'm sure the additional 1 foot becomes many hundreds of thousands of dollars, affecting bridge heights, right of way requirements, utilities, water drainage and runoff requirements, etc, etc.
I was surprised to discover that bridges carrying I-24 in Tennessee over at least one state highway had a clearance of only 13'-8," despite being built in 1969 and there being no apparent reason for there to be any major problem with providing more clearance. One could say it was for cost savings, but the highway is almost opulent in design, with wide medians and flashy bridges. Makes no sense to me.
Quote from: ixnay on May 09, 2016, 09:41:32 PM
The bridge over I-78 at exit 16 [Midway Road] in Bethel, PA was 13' 11" in August 2012 per GSV.
the overpass at Exit 17 (PA 419) also has a 13'11" clearance, and at Exit 19 (PA 183) there is a 13'10" clearance per GSV in August 2013.
My question: Was it typical to build bridges so low on those first generation interstates post Ike's interstate highway act?
It's worth noting that that section of I-78 was originally built as US 22.
Though UglyBridges appears to be correct about the completion date of the overpasses. Historic Aerials shows that in 1951 the current locations of exits 16 and 17 were simply intersections (not grade separated), and the divided highway had not yet been built as far east as exit 19. The next image in 1968 shows the road and interchanges all in more or less their current state.
But yes, overpasses of relatively low height can be found elsewhere on early interstates. Overpasses on NYC expressways are often not much more than 13'6", though they don't typically sign the clearances. Here's a GMSV image showing how the trucks fit. (https://www.google.com/maps/@40.8329553,-73.8593018,3a,20.2y,289.53h,85.9t/data=!3m6!1e1!3m4!1sSIBHqckqacvQ4SbgPjHGcw!2e0!7i13312!8i6656) Hell, here's another one up the road signed as 12'10" (https://www.google.com/maps/@40.8304297,-73.8513177,3a,55.7y,114.65h,82.59t/data=!3m6!1e1!3m4!1sR1tnkIruq-2bTWlLCaBTuw!2e0!7i13312!8i6656).
That said, the bridge may actually be a bit higher than the number on the sign. Lots of DOTs lowball those measurements to have a built in safety cushion. In some jurisdictions you also have a concept of "legal clearance", where maybe the bridge is 14'0" high, but if the sign says 13'6" you can get a ticket for driving a 13'7" truck under it even though you didn't hit anything.
Quote from: Jardine on May 10, 2016, 11:03:04 AM
I recall a story, possibly apocryphal, about the construction of the Erie Canal. The builders did all the easy stretches first and used up all their budget in the process.
Then they went back to the legislature and noted they had finished whatever % of the whole project and just needed an additional doodle to finish up things. And the money was forthcoming.
I might think the early years of interstate construction might have similarly focused on the 'easy parts' and the more of the system that was completed, the greater impetus to finish off the gaps (hello Wallace Idaho).
This is consistent with what I read somewhere about the Interstate building program in Texas. The state highway engineer understood the politics, so he wanted to finish the easy parts first and get long rural stretches built quickly, so that people could see the advantages of the new highways and would support continued funding for the system.
Quote from: wxfree on May 15, 2016, 08:15:52 PM
Quote from: Jardine on May 10, 2016, 11:03:04 AM
I recall a story, possibly apocryphal, about the construction of the Erie Canal. The builders did all the easy stretches first and used up all their budget in the process.
Then they went back to the legislature and noted they had finished whatever % of the whole project and just needed an additional doodle to finish up things. And the money was forthcoming.
I might think the early years of interstate construction might have similarly focused on the 'easy parts' and the more of the system that was completed, the greater impetus to finish off the gaps (hello Wallace Idaho).
This is consistent with what I read somewhere about the Interstate building program in Texas. The state highway engineer understood the politics, so he wanted to finish the easy parts first and get long rural stretches built quickly, so that people could see the advantages of the new highways and would support continued funding for the system.
US Interstates, Erie canal, I'd suspect the autobahn and probably going all the way back to the Apian Way if not earlier.
:-D
As I recall the Erie Canal was started in the west so that there would not be the temptation to say, "Eh, that's far enough" when it got halfway.
. . . and in addition to being built low, they were narrow too. No shoulder or pull off area.
Quote from: Duke87 on May 10, 2016, 11:15:01 PM
Here's a GMSV image showing how the trucks fit. (https://www.google.com/maps/@40.8329553,-73.8593018,3a,20.2y,289.53h,85.9t/data=!3m6!1e1!3m4!1sSIBHqckqacvQ4SbgPjHGcw!2e0!7i13312!8i6656)
Note sidewalks behind the single-plane barriers.
Most trucks at the time of this built would be 12'8. 13'6 wasn't a real standard, it was a design standard set for certain military vehicles that needed the room (my uncle told me years ago, forget which one). So, that's why 13'6 became the defacto standard for interstates. And because trucking companies knew most of the roads would handle 13'6 for interstate commerce, started buying box trailers with an extra 10 inches in height. Eventually the big tractors with taller sleeper compartments were built.
However, today, most states have a statutory limit higher than 13'6. Usually 14'0. And every state has different ways of measuring them (go ask New York and their ridiculous method that makes almost all bridge heights well lower than they really are and helps contribute to driver error in hitting the ones that are properly marked and with appropriate warnings. The 12'2 bridge on I-278 clears 13'6 trucks all day, but it's still signed 12'2 under the Brooklyn Bridge. And NYC wonders why drivers don't pay attention to the height signs.
Today, though, most bridges are now built for 16' or higher if can be. Unless it's a replacement and you just can't (sunken freeways through urban areas, etc).
I think the idea behind "legal clearance" is so that truckers who think their trailer is shorter than it really is don't hit the bridge. Basically, if the sign says the bridge is lower than the vehicle, they shouldn't be chancing it. And if they really, really want to, the ones with the actual clearance have a plaque saying "actual height" or something like that.
Quote from: wxfree on May 15, 2016, 08:15:52 PM
Quote from: Jardine on May 10, 2016, 11:03:04 AM
I recall a story, possibly apocryphal, about the construction of the Erie Canal. The builders did all the easy stretches first and used up all their budget in the process.
Then they went back to the legislature and noted they had finished whatever % of the whole project and just needed an additional doodle to finish up things. And the money was forthcoming.
I might think the early years of interstate construction might have similarly focused on the 'easy parts' and the more of the system that was completed, the greater impetus to finish off the gaps (hello Wallace Idaho).
This is consistent with what I read somewhere about the Interstate building program in Texas. The state highway engineer understood the politics, so he wanted to finish the easy parts first and get long rural stretches built quickly, so that people could see the advantages of the new highways and would support continued funding for the system.
Would another consideration for building a particular segment sooner than others have been utility for the military ??
It occurred to me today an early segment of I-29 in Iowa, from Council Bluffs to Hwy 30/Missouri Valley was used to transport Atlas missiles to and from Offutt AFB and missile silos located 1/2 between Missouri Valley and Beebeetown. With out that segment of interstate, would a 10' diameter Atlas on a missile trailer have fit under the truck peeling <13' high overpass south of Missouri Valley?
Or, instead of building that segment sooner to accommodate the missile base, was the missile base sited where it was because, coincidentally, the Interstate was already completed ?
(https://www.aaroads.com/forum/proxy.php?request=http%3A%2F%2Fmedia.dma.mil%2F2015%2FApr%2F09%2F2001037328%2F-1%2F-1%2F0%2F150409-A-CE999-101.JPG&hash=c4a051dfca0d09a493c016b8f4da766956b8f5a7)
Like mentioned above, I think these bridges were built pre-interstate.
That would explain why in NC the section from Eastover to Kenly had the low clearance signs at each overpass listing the height. I cannot remember the exact numbers, but as a kid when we went to Florida I found that to be fascinating as NJ only used them on the old RR overpasses. That section was one of, or if not, the oldest section of I-95 in NC to open to traffic hence its many interchanges as well.
Would you be willing to say that the PA turnpike was the one that set the standard at 13 Foot 6? as that is the maximum height they allow on the road.
It's interesting to note that about 30-35 years ago AASHTO and/or FHWA allowed the "grandfathering" of the former US 395 freeway between Riverside & Colton (CA) as I-215 (renumbered from I-15E), including a series of bridges in the Grand Terrace area that are between 14-4 and 14-6 clearance in both directions (this section was built circa 1960-61, when such clearances were common). I haven't been on this section in about 4 years, but AFAIK the low clearance overcrossings remain as such. I guess there wasn't a firm 25-year commitment for reconstruction in place when the Interstate designation was processed. This is in contrast to several miles east along I-10, where a series of low bridges in the Yucaipa area (some as low as 14-1 and also dating from about 1961-62) were rebuilt in the late '90's and early '00's. Of course, I realize that a trunk route should & does claim priority, but a significant amount of commercial traffic turns south on 215 from 10 (most heading to CA 91 and Orange County/Long Beach). I'm just surprised that no plans to alleviate the clearance issue have yet emerged. By the way, if anyone has any knowlege of current or pending upgrades to this section of route, please feel free to respond with your info!
Quote from: sparker on June 19, 2016, 12:39:48 AM
It's interesting to note that about 30-35 years ago AASHTO and/or FHWA allowed the "grandfathering" of the former US 395 freeway between Riverside & Colton (CA) as I-215 (renumbered from I-15E), including a series of bridges in the Grand Terrace area that are between 14-4 and 14-6 clearance in both directions (this section was built circa 1960-61, when such clearances were common). I haven't been on this section in about 4 years, but AFAIK the low clearance overcrossings remain as such. I guess there wasn't a firm 25-year commitment for reconstruction in place when the Interstate designation was processed. This is in contrast to several miles east along I-10, where a series of low bridges in the Yucaipa area (some as low as 14-1 and also dating from about 1961-62) were rebuilt in the late '90's and early '00's. Of course, I realize that a trunk route should & does claim priority, but a significant amount of commercial traffic turns south on 215 from 10 (most heading to CA 91 and Orange County/Long Beach). I'm just surprised that no plans to alleviate the clearance issue have yet emerged. By the way, if anyone has any knowlege of current or pending upgrades to this section of route, please feel free to respond with your info!
The PA Turnpike Northeast Extension was allowed to become I-476 in 1996 with the completion of the new tunnel. No way to increase the bridge height from 13ft 6 due to the tunnels on the system, would be a waste of money.
Also, you do have the part of i-278 in NYC that is part of the parkway system due to routing issues. No trucks at all.
Used to be no trucks but at some point trucks that are low enough to fit under the bridges were allowed.
Quote from: vdeane on June 19, 2016, 03:16:14 PM
Used to be no trucks but at some point trucks that are low enough to fit under the bridges were allowed.
by trucks i mean tractor-trailers.
Quote from: SteveG1988 on June 23, 2016, 09:38:49 PM
Quote from: vdeane on June 19, 2016, 03:16:14 PM
Used to be no trucks but at some point trucks that are low enough to fit under the bridges were allowed.
by trucks i mean tractor-trailers.
Hell, 53' trucks are banned on everything in New York City other than I-95, the Clearview, the LIE east of the Clearview, the Van Wyck, and Sunrise Highway.
Quote from: cl94 on June 23, 2016, 10:03:47 PM
Quote from: SteveG1988 on June 23, 2016, 09:38:49 PM
Quote from: vdeane on June 19, 2016, 03:16:14 PM
Used to be no trucks but at some point trucks that are low enough to fit under the bridges were allowed.
by trucks i mean tractor-trailers.
Hell, 53' trucks are banned on everything in New York City other than I-95, the Clearview, the LIE east of the Clearview, the Van Wyck, and Sunrise Highway.
Oh...yeah umm about that. They just turn a blind eye to it. As most trailers are 53 foot now.
Quote from: SteveG1988 on June 23, 2016, 10:19:27 PM
Quote from: cl94 on June 23, 2016, 10:03:47 PM
Quote from: SteveG1988 on June 23, 2016, 09:38:49 PM
Quote from: vdeane on June 19, 2016, 03:16:14 PM
Used to be no trucks but at some point trucks that are low enough to fit under the bridges were allowed.
by trucks i mean tractor-trailers.
Hell, 53' trucks are banned on everything in New York City other than I-95, the Clearview, the LIE east of the Clearview, the Van Wyck, and Sunrise Highway.
Oh...yeah umm about that. They just turn a blind eye to it. As most trailers are 53 foot now.
Yeah, I've seen a couple of 53-footers on Manhattan the last couple of times I was down there.
If a trailer isn't dedicated to NY it doesn't pay to have it be a 48 footer.
NYC has a 55 foot overall length limit as well. But, any vehicle recognized as under STAA (interstate commerce) has normal restrictions to the National Network and travel to and from the network. There's 53' trailers all over NYC whenever I'm there. Many even parking on the streets around Major Deegan near the Cross Bronx, and along I-95 near the bus terminal.
The truck restriction is solely for domiciled trucks to NY state in and out of the city or strictly within NYC.
Regarding overhead bridge clearances, the Interregional Highways report of 1944 recommended 14ft, which according to the few references I've seen was carried into the early Interstate construction of the late 1950s. Current standard (dated 2005 from AASHTO) is 16ft.
Regarding the comment on bridge shoulders, full-width shoulders (generally 10ft outside and 4ft inside) were not required until the 1967 Highway Act. And on longer bridges (200ft or longer), a narrower shoulder can be allowed as long as it's no less than 4ft.
Quote from: cl94 on June 23, 2016, 10:03:47 PM
Quote from: SteveG1988 on June 23, 2016, 09:38:49 PM
Quote from: vdeane on June 19, 2016, 03:16:14 PM
Used to be no trucks but at some point trucks that are low enough to fit under the bridges were allowed.
by trucks i mean tractor-trailers.
Hell, 53' trucks are banned on everything in New York City other than I-95, the Clearview, the LIE east of the Clearview, the Van Wyck, and Sunrise Highway.
Hmm, I don't see it on Sunrise:
http://www.nyc.gov/html/dot/downloads/pdf/2015-06-08-truck-map-combined.pdf
Somehow though I imagined if they had actually completed the Clearview they wouldn't restrict them south of the LIE.
Quote from: Sykotyk on July 02, 2016, 10:11:00 PM
NYC has a 55 foot overall length limit as well. But, any vehicle recognized as under STAA (interstate commerce) has normal restrictions to the National Network and travel to and from the network. There's 53' trailers all over NYC whenever I'm there. Many even parking on the streets around Major Deegan near the Cross Bronx, and along I-95 near the bus terminal.
Well, the terminal is above I-95. If they have to make deliveries nearby, so be it.
When i was a kid every overpass had clearace listed like it was a requirement. Now none do
LGMS428
Quote from: jwolfer on December 17, 2016, 09:09:05 PM
When i was a kid every overpass had clearace listed like it was a requirement. Now none do
LGMS428
Really? Because I find that a lot of them have clearances listed that you wouldn't think are necessary. On the other hand, I just found out that the former Atlanta and West Point Railroad bridge over US 29 in Grantville, Georgia is 14'9" (higher than I thought), and the info about this is some barely visible stenciling on one side of that gray bridge. They need some normal MUTCD signage there.
Quote from: jwolfer on December 17, 2016, 09:09:05 PM
When i was a kid every overpass had clearace listed like it was a requirement. Now none do
LGMS428
Bridges with clearances below 16' are generally posted on CA state highways; this extends to the streets passing under freeways. Some county/local roads are posted similarly as well -- some jurisdictions are more thorough than others.
NJ has its fare share of "scrapper" bridges on non-interstates. https://goo.gl/maps/v3N3aUQHJCE2
There don't seem to be too many examples on Interstates. Surprising, given the urban nature and age of most of the roads. NJ seems to sign any heights below 14.5 feet. Clearances on Interstate overpasses are generally low on only the rightmost lane. Some overpasses go slightly below 14ft in those cases.
Since we have some overlap with railfans here at AARoads, they might know if this hypothesis is at all plausible:
Those early, lower overpass clearances seem close to a standard vertical clearance for the railroads at the time. I don't know what height the railroads were using at the time, in the days before double-stack container freight, but it seems similar. Perhaps they used that as a baseline initially?
The thinking was probably, "Well if a rail car can fit under it, that should handle any truck out there, right?"
Quote from: ixnay on May 09, 2016, 09:41:32 PM
jeffandnicole and I had this exchange on the thread on the Northeast board about speed limits in Pennsylvania increasing to 70 mph...
Quote from: jeffandnicole on May 03, 2016, 10:14:30 PM
Quote from: ixnay on May 03, 2016, 09:51:33 PM
The bridge over I-78 at exit 16 [Midway Road] in Bethel, PA was 13' 11" in August 2012 per GSV. I stayed at the Comfort Inn at that exit a couple of nights in the summer of 2010 and had "fun" watching the semis barely clear the overpass. I would not want have been atop a semi trailer, even laying down. This would've been a perfect place for an overhead "If you hit that sign, you will hit that bridge" sign.
ixnay
Since the legal height is 13' 6" and every truck would be built not to exceed that height, there should be no reason why that bridge would get hit.
Well...
...the overpass at Exit 17 (PA 419) also has a 13'11" clearance, and at Exit 19 (PA 183) there is a 13'10" clearance per GSV in August 2013*.
The Exit 16, 17, and 19 overpasses were all built in the 1958-59 period per uglybridges.com.
My question: Was it typical to build bridges so low on those first generation interstates post Ike's interstate highway act? (Too bad uglybridges doesn't give the bridges' clearances over what they're crossing.)
*GSV in August 2013 also showed the bridge at exit 13 (PA 501) as being under reconstruction, perhaps adding an inch or 2 to the clearance.
ixnay
The large trucks of the 1950s and 1960s were considerably smaller than those allowed later on.
Quote from: Beltway on May 15, 2017, 03:55:06 PM
The large trucks of the 1950s and 1960s were considerably smaller than those allowed later on.
So the better question is, "Why did they start building trucks taller than bridge clearances on major highways?"
Quote from: kkt on May 15, 2017, 05:06:42 PM
Quote from: Beltway on May 15, 2017, 03:55:06 PM
The large trucks of the 1950s and 1960s were considerably smaller than those allowed later on.
So the better question is, "Why did they start building trucks taller than bridge clearances on major highways?"
Clearances varied from state to state. Some states could handle the taller trucks, so there were regions where these trucks could operate. Other regions where they could not.