Lets talk about the Squirrel Hill Tunnels (Pittsburgh, Swissvale: maintenance, cost of)

[wpipkins]

Originally Posted by Gnutella

The Pennsylvania Turnpike Commission estimated the cost of boring two new Allegheny Mountain Tunnel portals at $280M, and those new portals would be roughly the same length as the Squirrel Hill Tunnel, so I seriously doubt that enlarging the Squirrel Hill Tunnel portals would cost in the billions. Maybe reconstructing I-376 between Robinson and Monroeville to modern Interstate standards would cost a couple billion (it's still necessary and long overdue, by the way), but enlarging a couple of tunnel portals should not. In fact, you could enlarge both the Squirrel Hill and Fort Pitt Tunnels for less than $1B.

The allegheny tunnel does not run under a urban city neighborhood with a new housing developments adjacent to it. Boring in a rural area will be alot cheaper.

[BrianTH]

Originally Posted by Gnutella

so I seriously doubt that enlarging the Squirrel Hill Tunnel portals would cost in the billions.

Oh, it definitely would. You can't make comparisons to random other tunnel projects--you're talking about going under a densely-developed neighborhood, while you still need to use the existing lanes, and also dealing with the approaches (which on one side include a pretty big bridge).

Maybe reconstructing I-376 between Robinson and Monroeville to modern Interstate standards would cost a couple billion (it's still necessary and long overdue, by the way), but enlarging a couple of tunnel portals should not. In fact, you could enlarge both the Squirrel Hill and Fort Pitt Tunnels for less than $1B.

Of course there is no point widening the tunnels unless you also widened the roads/bridges to and from them.

Anyway, a 2002 study found that widening the Fort Pitt tunnel and related highways would cost half a billion. So, no, you can't do that and the Squirrel Hill tunnel for less than $1B in 2011 (and it wouldn't be 2011 costs you were looking at by the time any of this could conceivably be done).

[TechieTransplant]

Originally Posted by thinkerdan

I've made it my mission to avoid these tunnels as much as possible when commuting from the Monroeville area in/out of Oakland (on a daily basis). I'm curious what everybody thinks about the traffic messes that occur around these tunnels on a daily (hourly?) basis, and what can actually be done about it. Of course everybody says it's because all the drivers "tap" their brakes when entering the tunnels. Do you all believe this to be the case, or does anybody have any additional insight into traffic dynamics which could be worsening the problems. Due to the geographical location, it seems as though rebuilding/widening the tunnels will never be a viable option. I've heard that there are plans to increase the height of the tunnels, but I'm not sure how much this will really help. Do any of you see any hope in the future for a solution to the traffic nightmare that is the Squirrel Hill Tunnels?

-Thanks
-Dan

You get the usual engineering minded people here saying it's this or that, but bottom line, it's because of two things; fear of allowing your vehicle roll freely down even the slightest of inclines, and fear of driving through confined spaces.

[Craziaskowboi]

Originally Posted by BrianTH

Oh, it definitely would. You can't make comparisons to random other tunnel projects--you're talking about going under a densely-developed neighborhood, while you still need to use the existing lanes, and also dealing with the approaches (which on one side include a pretty big bridge).

But I'm talking about the tunnel, not the tunnel and the bridge.

Originally Posted by BrianTH

Of course there is no point widening the tunnels unless you also widened the roads/bridges to and from them.

You can widen the tunnel in preparation for widening the highway. In fact, widening the tunnels first would be best because everything gets easier after that, at least from a construction standpoint. You can bore the tubes large enough for three lanes plus shoulders, but paint the lines for two lanes in the interim until the rest of the highway is widened.

Originally Posted by BrianTH

Anyway, a 2002 study found that widening the Fort Pitt tunnel and related highways would cost half a billion. So, no, you can't do that and the Squirrel Hill tunnel for less than $1B in 2011 (and it wouldn't be 2011 costs you were looking at by the time any of this could conceivably be done).

Again, I'm talking about the tunnel, not the tunnel plus a bunch of other stuff. And like I said, if you have a highway with tunnels and the highway needs to be widened, you widen the tunnel first, and then you widen the rest of the highway. It's the same way the Pennsylvania Turnpike Commission does preparatory work for widening a segment of the Turnpike by first rebuilding all overpasses to fit 124' of right-of-way underneath them. The highway itself doesn't get widened until later.

[TechieTransplant]

Originally Posted by Gnutella

They need to be enlarged to hold three lanes plus four-foot shoulders on each side.

The main reason people tap their brakes going into the tunnels is because there are no shoulders inside. I guarantee you that if the portals were large enough to include at least four-foot shoulders on each side, there'd be far less brake-tapping entering them.

I love these responses. You can blow the roof of all the tunnels, raise the roof, and add 15 lanes of traffic in each direction, and it won't do a damn thing. Pittsburgh drivers are the most timid drivers you will see. People drag their brakes down even the slightest grades, they drag their brakes around the most simple curves in the road, and they drag their brakes in tight traffic situations. End of story

[BrianTH]

Originally Posted by Gnutella

But I'm talking about the tunnel, not the tunnel and the bridge.

Any real world project would require both to actually get the full benefit of a widened tunnel, and so that's the cost you have to consider, even if you decide to break the project into multiple phases.

In other words, if you try to sell people on a purportedly cheaper tunnel-only project, they will figure out pretty soon for themselves that they need to include the road and bridge costs before agreeing that your proposal makes sense.

[BrianTH]

Originally Posted by scottrpriester

End of story

Except the tunnels are not congested 24/7. and are regularly most congested at peak travel times.

That does in fact imply that enough additional peak capacity, holding the number of peak cars fixed, would temporarily relieve congestion. Unfortunately, it is unlike the number of peak cars would remain the same for long, which is why this ultimately wouldn't work. But the reason you are giving doesn't make sense given what we can observe (that the tunnels are not always congested, and are predictably most congested at peak times).

[ElijahAstin]

376 is a nightmare in general. Whenever I drive in from Philadelphia, I almost always have to get off at the Edgewood/Swissvale exit, lest I desire to spend an extra 45 minutes in stop-and-go highway traffic.

[ML North]

Originally Posted by scottrpriester

I love these responses. You can blow the roof of all the tunnels, raise the roof, and add 15 lanes of traffic in each direction, and it won't do a damn thing. Pittsburgh drivers are the most timid drivers you will see. People drag their brakes down even the slightest grades, they drag their brakes around the most simple curves in the road, and they drag their brakes in tight traffic situations. End of story

Clearly there are traffic bottlenecks all over the country. Also, regardless of whether or not you choose to accept it, the dynamics of these bottlenecks are far more complex than you think they are.

2010 Annual Report -- 100 Worst Bottlenecks (http://www.inrix.com/scorecard/Top100Bottlenecks.asp - broken link)

[mjost7]

Originally Posted by scottrpriester

You get the usual engineering minded people here saying it's this or that, but bottom line, it's because of two things; fear of allowing your vehicle roll freely down even the slightest of inclines, and fear of driving through confined spaces.

The "fear" is justified. There'd be more crashes if drivers were somehow forced to maintain the same headways as they do outside of the tunnels with the wider shoulders. This kind of thing happens everywhere highway capacity is restricted.

And I agree this is a frustrating feature of I-376 and of natural driver behavior. That's one reason why I use the East Busway to commute downtown most days.