Group pushing for a Plattsburgh (NY) - Grand Isle (VT) bridge

[froggie]

Not fantasy.  There's a group who's pushing local and state officials to build a bridge between Plattsburgh, NY and Vermont (most likely at Grand Isle):

http://www.mychamplainvalley.com/news/fighting-for-a-bridge-new-committee-wants-bridge-built-between-plattsburgh-burlington/970670875

[Alps]

It would pretty much have to run Cumberland Head NY to Gordon Landing VT. By far the shortest gap to bridge in the northern lake. But is this another Rooftop Highway - good idea but not enough traffic to justify?

[webny99]

I like the idea in theory, but am skeptical it will come to pass without substantially more support.

Volume could be hard to predict, but I'm sure it would be higher than the current ferry. What would a minimum AADT be to justify it?

[Rothman]

Ugh. 

Reminds me of a NYSDOT bureau director who bemoaned the fact it was cheaper to move people to one side of the Crown Point bridge to the other than to replace the bridge.

Bridge to nowhere also comes to mind.

[Alps]

I like the idea in theory, but am skeptical it will come to pass without substantially more support.

Volume could be hard to predict, but I'm sure it would be higher than the current ferry. What would a minimum AADT be to justify it?

I wonder if the answer to that question depends on whether it was tolled or not. Crown Point only gets 3k-4k. In my head I had a higher number than that, but given the traffic on US 2 crossing to the north, I just don't see the demand there. Sure, it's a convenience for locals, but I would say "if someone wants to build this and collect toll revenues, we'll support them, but we won't pay for it." I bet no one takes that offer.

[froggie]

It would pretty much have to run Cumberland Head NY to Gordon Landing VT. By far the shortest gap to bridge in the northern lake.

While technically not insurmountable, such a location would still require a bridge almost 2 miles long, with about a mile of that in water over 100ft deep.

Volume could be hard to predict, but I'm sure it would be higher than the current ferry. What would a minimum AADT be to justify it?

Given the expected price tag (the group is floating $1B as an initial, and even that may be generous), higher than you'd like.

Since Rothman mentioned the Lake Champlain Bridge (NY 185/VT 17), it should be noted that NYSDOT/VTrans spent ~$70 million for a new bridge that carries (per VTrans) 4,200 vpd.  Extrapolating that cost-benefit out to a $1B bridge would yield a 60,000 vpd.  For the record, that's higher than the highest AADT segment in the entire state of Vermont.

[RobbieL2415]

Extend I-189 to I-87 in Plattsburgh via an upgraded US 2 bridge and via a new bridge to replace the Grand Isle-Cumberland Head Ferry?

[Roadgeek Adam]

Extend I-189 to I-87 in Plattsburgh via an upgraded US 2 bridge and via a new bridge to replace the Grand Isle-Cumberland Head Ferry?

I-189 wouldn't exactly have a normal route. It would be mostly concurrent with I-89.

Regardless, where the hell would you build a new freeway?

[RobbieL2415]

Extend I-189 to I-87 in Plattsburgh via an upgraded US 2 bridge and via a new bridge to replace the Grand Isle-Cumberland Head Ferry?

I-189 wouldn't exactly have a normal route. It would be mostly concurrent with I-89.

Regardless, where the hell would you build a new freeway?

Decommission current I-189.  Have the new 189 begin just north of US 2 (Exit 17).  US 2 joins I-189 at the start of the straightaway to what would be a new bridge and remove the quasi bridge/jetty thing currently there. US 2 leaves I-189 to the NW of that housing development and follows its current alignment from there.  189 would parallel it to the vic. of VT 314, then turn NW to the Gordon Landing ferry terminal (said ferry would be eliminated) and cross Lake Champlain once more to the ferry terminal on the other end.  NY 314 would be four-laned and brought to Interstate standards, the interchange at US 9 would be grade-seperated and I-189 would end just west of there at I-87.

[Alps]

Please keep this on topic instead of fictional, thanks.

[wdcrft63]

I don't know the area, so this is coming from the Peanut Gallery. However, it seems to me that widening US 2 to four lanes would be cheaper than building the bridge, and if there's not enough traffic to require four-laning US 2 then I don't see how there could possibly be enough traffic to justify a $1B bridge.

[vdeane]

The US 2 bridge is 20 miles to the north of the existing ferry at Cumberland Head/Gordon Landing (and 35 miles north of the Burlington-Port Kent ferry), so it's still significantly faster to take the ferry than do 40 miles extra driving to use the bridge, especially since the stated purpose of building a new bridge would be to better connect Burlington and Plattsburgh.

[froggie]

^ The exception to that being if you're unlucky and just miss the ferry when it's on 40-minute headways (10pm-5am, except 6:20am on Sundays).  At the typical 12-15minute headways during the week (5:30am-8pm), it saves at least 20 minutes over driving to Rouses Point.

That said, he's got a point.  I just don't see the traffic volume or travel demand to warrant a new bridge.

[webny99]

What are traffic volumes on the current ferry?
Are they publicly available in some form?

[kalvado]

What are traffic volumes on the current ferry?
Are they publicly available in some form?

Ferry is operated as private company, and I don't see any data.
Road going into Cumberland head has 9k/day count. Not all that traffic is crossing, though. three roads going to ferry add up to 6K/day. Probably something along those lines.
That adds up to about 2 million vehicles/year paying $10.25 one way per car. Bridge cost is equal to about 50 years of ferry revenue..
Not very encouraging, but not totally a non-starter as well.

Wiki has a reference to (paywalled) article from 2001, when Chuck Schumer was on the issue. Ferry company was (predictably) opposed to idea. Wiki has a short quote, though:

About 807,000 vehicles used the ferry between Cumberland Head and Grand Isle, Vt., last year (2000) an all-time high.

- 1/3 of my estimate.

[Duke87]

While technically not insurmountable, such a location would still require a bridge almost 2 miles long, with about a mile of that in water over 100ft deep.

I'm measuring only about 1.4 miles from the NY ferry landing straight across. Presumably any such bridge would follow such an alignment rather than simply connecting the two existing ferry terminals, which involves crossing the lake at an angle and making the bridge longer than it needs to be.

Given the expected price tag (the group is floating $1B as an initial, and even that may be generous), higher than you'd like.

Why would this cost more than 10x what the new Crown Point Bridge did when it's (potentially) less than 4x the length?

This smells to me like one of those things that reasonably should, and in any other first world nation would, cost a fraction of the price tag that's being floated for it, but is ballooned to the point of not being worth it here because this is the land of $10,000 toilet seats.

[froggie]

Per VTrans traffic volumes, VT 314 had 3,300 AADT south of the ferry, around 700 north of the ferry, with both figures from 2016.  A local traffic count on Bell Hill Rd from 2017 shows 173 vpd.  Assuming that not all of those vehicles are heading to/from the ferry, average daily ferry traffic cannot be higher than 4,000.

I'm measuring only about 1.4 miles from the NY ferry landing straight across. Presumably any such bridge would follow such an alignment rather than simply connecting the two existing ferry terminals, which involves crossing the lake at an angle and making the bridge longer than it needs to be.

I got 1.7 specifically along the most likely alignment that won't impact underwater utilities.  Approach work will also push the mileage figure closer to 2.

Why would this cost more than 10x what the new Crown Point Bridge did when it's (potentially) less than 4x the length?

For starters, the Crown Point Bridge doesn't go through close-to-a-mile of 100+ft deep water.  Second, because of the difficulty of getting large loads onto/through Grand Isle, most of the heavy staging would likely have to be on the New York side, unless they were floated up-lake or down-lake from elsewhere.  Either way, add a bit of expense there as well.

[vdeane]

Traffic Data Viewer has a 2015 count on former NY 314 not too far from the ferry with an AADT of 2927; the counts for the local roads were all taken near the north end of NY 314, so I wouldn't count on too much traffic coming from those roads.

^ The exception to that being if you're unlucky and just miss the ferry when it's on 40-minute headways (10pm-5am, except 6:20am on Sundays).  At the typical 12-15minute headways during the week (5:30am-8pm), it saves at least 20 minutes over driving to Rouses Point.

That said, he's got a point.  I just don't see the traffic volume or travel demand to warrant a new bridge.

I don't disagree that the traffic counts are low here to justify a bridge, but I don't think the US 2 crossing is comparable (which, incidentally, had an AADT of 4204 in 2015, and has been decreasing every year since at least 2006) due to its distance away.

The bridge proponents seem to be counting on the idea that a bridge would make people start commuting to Burlington from Plattsburgh.  It's still a pretty long commute, though, even if a bridge was built.

[froggie]

Longer, but not horrible.  A bridge at/near the ferry site would result in about 30 miles between downtown Plattsburgh and most employment centers in the Burlington area.

They may be banking on the fact that there's better employment opportunity in Chittenden County while cost of living is somewhat lower (but noticeably lower for housing) in Plattsburgh.

[Beltway]

I'm measuring only about 1.4 miles from the NY ferry landing straight across. Presumably any such bridge would follow such an alignment rather than simply connecting the two existing ferry terminals, which involves crossing the lake at an angle and making the bridge longer than it needs to be.

At say $100 million per mile for a 2-lane bridge that would be $140 million.  Why would it be any more?

[froggie]

^ For reasons I cited above.  A bridge would be closer to 2 miles (I pegged shore-to-shore at 1.7) because of underwater utilities in the vicinity of the existing ferry.  Also, as I noted above, there is a significant stretch of water over 100ft deep.  That would either require deep bridge piers or a longer main span, either (or both) of which would bump the cost up a bit.

While I don't think a bridge, if built now, would be $1B in cost, I also think Anthony's assumption of $100M/mile is lowballing it.  Here's my rationale:

The Crown Point Bridge was approximately $70M for a span that, including approaches, is roughly 0.5mi in length.  For simplicity, let's double that, for what is basically $140M per mile.

As I noted above, a Plattsburgh-Grand Isle span would have more significant challenges with water depth and length than the Crown Point Bridge, so (unless someone has better figures to offer), let's say this ups the price by $60M per mile (~43%).  For simplicity, let's round this to $200M per mile.

The cited figure (from news reports) for the Crown Point Bridge was just construction.  There are also right-of-way, utility and preliminary engineering costs that come ahead of that.  MnDOT (the agency I'm most familiar with) typically uses a percentage ranging from 12-20% of construction costs to account for this.  Given the scope of this potential bridge, 20% is reasonable, bringing us to $240M per mile.

Also as noted above (and in a previous post), a shore-to-shore length of about 1.7 miles would be needed to avoid the underwater utilities.  For simplicity, let's presume that not much is needed for approach work on each side (let's say 0.05mi = 264ft).  So a total bridge+approach length of 1.8 miles.

$240M/mi * 1.8 miles = $432M.  I do see this as a fairly reasonable "first guess" cost for such a bridge.

[MNHighwayMan]

What are these underwater utilities and why can't they be relocated? Sure, relocating them costs money, but surely it can't be more than the expense of a longer bridge.

[Duke87]

$432M sounds more reasonable than $1B.

(and that wasn't me who suggested $100M/mile, it was Beltway quoting me)

What are these underwater utilities and why can't they be relocated? Sure, relocating them costs money, but surely it can't be more than the expense of a longer bridge.

Well, they are underwater. Relocating them would not be cheap.

[MNHighwayMan]

What are these underwater utilities and why can't they be relocated? Sure, relocating them costs money, but surely it can't be more than the expense of a longer bridge.

Well, they are underwater. Relocating them would not be cheap.

Right, but I have a hard time believing that, if we use froggie's numbers, that the cost of the extra 0.3 miles of bridge, $72 million (0.3 miles * $240M/mile) is smaller than the cost of moving some fiber optic lines or pipelines or whatever it is that's down there.

[Beltway]

Economies of scale in a construction project.  Plus either bridge has only one high level section.

I would not necessarily double the per mile cost for a 2-mile bridge as compared to a 1-mile bridge.