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Memphis: Walnut Grove - 45mph parkway?

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Chris Lawrence

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Nov 20, 2002, 2:37:53 PM11/20/02
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The geniuses who run Shelby Farms have come out with this whopper of a
proposal:

http://www.gomemphis.com/mca/local_news/article/0,1426,MCA_437_1556386,00.html

"The Shelby Farms board waded into the debate over the proposed road
through the park Tuesday, asking for a lower speed limit and a design
that conforms to the land.

The board, which chairman Ron Terry had promised would take a more
active role in the road discussion, approved a resolution that asks
the city and county to:

# Request that the Tennessee Department of Transportation set the
road's speed limit no higher than 45 mph.

"What I'm trying to get them to do is set the speed limit now," Terry
said. "So that the engineers in TDOT understand that they're not
building an expressway."

# Request that the road be designed as a parkway with no structures
higher than grade level. This means, Terry said, that the board wants
to see the planned interchanges depressed to the level of the
surrounding land.

# Request that the need for a 250-foot right-of-way for the road be
re-examined so that the road is no wider than Humphreys Bouldevard,
which averages about 114 feet of right-of-way."

Ok, the last two aren't that bad, but 45 mph would be a 10 mph speed
limit drop from the existing road, which has at-grade intersections
and no safety features to speak of. And, contra Ron Terry, TDOT
*should* be building a freeway, because existing Walnut Grove Rd
handles 58,600 ADT between I-240 and Humphreys Blvd (approximately the
same as Sam Cooper Blvd and nearly 50% more than U.S. 78 south of
I-240) and 39,180 ADT near Germantown Parkway.


Chris - http://blog.lordsutch.com/

John Lansford

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Nov 20, 2002, 3:25:56 PM11/20/02
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ch...@lordsutch.com (Chris Lawrence) wrote:

>The geniuses who run Shelby Farms have come out with this whopper of a
>proposal:
>
>http://www.gomemphis.com/mca/local_news/article/0,1426,MCA_437_1556386,00.html
>
>"The Shelby Farms board waded into the debate over the proposed road
>through the park Tuesday, asking for a lower speed limit and a design
>that conforms to the land.
>
>The board, which chairman Ron Terry had promised would take a more
>active role in the road discussion, approved a resolution that asks
>the city and county to:
>
># Request that the Tennessee Department of Transportation set the
>road's speed limit no higher than 45 mph.
>
>"What I'm trying to get them to do is set the speed limit now," Terry
>said. "So that the engineers in TDOT understand that they're not
>building an expressway."

Sounds like they want a curb and gutter road instead of a freeway or
expressway.

># Request that the road be designed as a parkway with no structures
>higher than grade level. This means, Terry said, that the board wants
>to see the planned interchanges depressed to the level of the
>surrounding land.

Kind of hard to drain an interchange that is below the ground level.

># Request that the need for a 250-foot right-of-way for the road be
>re-examined so that the road is no wider than Humphreys Bouldevard,
>which averages about 114 feet of right-of-way."

A 114' R/W would have to include the following items:

At least four lanes plus a 16' median, or five paved lanes. That is
either 60' or 64' depending on the design.

Curb and gutter on both sides of the road. That's an additional 4'.

The berm width behind the curb. That width can range from 4' to 12',
but if they want sidewalk they need to go with at least 8' berms.
That's another 16' for a total of 84' if you go with the basic design.

If the city wants wider lanes for bicycles (another 2' on each side)
or parking lanes (add 8' for each side), or dedicated bicycle lanes
(4'-8' depending on the area), you can easily run out of R/W.

>Ok, the last two aren't that bad, but 45 mph would be a 10 mph speed
>limit drop from the existing road, which has at-grade intersections
>and no safety features to speak of. And, contra Ron Terry, TDOT
>*should* be building a freeway, because existing Walnut Grove Rd
>handles 58,600 ADT between I-240 and Humphreys Blvd (approximately the
>same as Sam Cooper Blvd and nearly 50% more than U.S. 78 south of
>I-240) and 39,180 ADT near Germantown Parkway.

A freeway, OTOH, would require a lot more R/W width. Say four lanes at
12' each, a 16' median with a barrier, outside shoulder widths of 12'
(10' paved), and a 30' clear recovery zone on each side, and you're
looking at 148' at a minimum. It would be a better design if the
median were wider (46' would provide room for two more lanes in the
future), but it would take up more R/W.

John Lansford, PE

The unofficial I-26 Construction Webpage:
http://users.vnet.net/lansford/a10/

Don Hagstrom

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Nov 21, 2002, 3:42:42 AM11/21/02
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What route number would apply to this proposed freeway / parkway--what
location would it be at?

--
Don Hagstrom
Director, Friends of Southern California's Highways
www.fixtraffic.org

"Chris Lawrence" <ch...@lordsutch.com> wrote in message
news:1532dc0c.02112...@posting.google.com...

Adam Froehlig

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Nov 21, 2002, 6:14:03 AM11/21/02
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> What route number would apply to this proposed freeway /
> parkway--what location would it be at?

Walnut Grove Rd is TN SSR 23, if I'm not mistaken. The proposed
freeway/parkway (whichever happens, IF it happens) would be along the
road's existing alignment.

Chris: isn't Walnut Grove Rd 6 lanes already through some of that
area? Or is it still 4?

Froggie | Virginia Beach, VA | http://www.ajfroggie.com/roads/

Chris Lawrence

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Nov 21, 2002, 1:39:01 PM11/21/02
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On Thu, 21 Nov 2002 11:14:03 +0000, Adam Froehlig wrote:

>> What route number would apply to this proposed freeway /
>> parkway--what location would it be at?
>
> Walnut Grove Rd is TN SSR 23, if I'm not mistaken. The proposed
> freeway/parkway (whichever happens, IF it happens) would be along the
> road's existing alignment.

SSR 23 actually ends today at I-240, although I believe it used to extend
further east, at least to SSR 177 (then Germantown Road).

The new "freeway" being talked about by TDOT would bypass Shelby Farms to
the north. I'd have to sketch a map, but basically it would turn NE to
the northern edge of Shelby Farms, run due E parallel to Mullins Station
Rd, then turn SE to reconnect to the existing alignment just west of
Germantown Parkway near the Agricenter.

This is a compromise plan worked out by TDOT after lobbying from ex-county
mayor Jim Rout and the "Save Shelby Farms" crowd. The original idea was to
upgrade existing Walnut Grove to a freeway and also build "Kirby-Whitten
Parkway" (reconstructed Whitten Rd, originally planned to flow directly
into Kirby Pkwy south of the Wolf River, but the part south of Walnut
Grove to Humphreys Blvd was already killed). Since this would "destroy
the park" (guffaw), the idea was to move the road to avoid cutting the
park up. The existing alignment would be torn out, although I suspect a
bike path or something would probably be put in its place.

It's pretty indirect but if they built it as a real freeway it would
probably be useful. The "parkway" concept is basically to do what they
did south of the Wolf River with Humphreys Blvd/Wolf River Parkway (it
changes back to its "planning name" when it enters Germantown); it's OK,
but it's an underposted 45 mph drag strip (no bike lanes) with no access
control to speak of.

Wolf River Parkway has its own controversies; it's supposed to be built all the
way to the Collierville-Arlington Pkwy (future SPR 385/I-669) eventually,
and bits are already in place, but a gap in Germantown is proving to be
unlikely to be finished because the brain donors who run Germantown
established a nature preserve in the right of way and now can't get rid of
it, so they're stuck either bulldozing a golf course or building it
through Memphis with 2 extra bridges to cross & re-cross the Wolf River.

> Chris: isn't Walnut Grove Rd 6 lanes already through some of that
> area? Or is it still 4?

6 lanes east to the Humphreys Blvd intersection just west of the Wolf
River, then 4 lanes with a big median to Germantown Parkway (SSR 177). The
Germantown Pkwy overpass is six lanes wide (with a full freeway design, so
actually wider including the shoulders), but striped for four. (It's was
also TN's first SPUI.)


Chris
--
Chris Lawrence <ch...@lordsutch.com> - http://blog.lordsutch.com/

Chris Lawrence

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Nov 21, 2002, 1:44:25 PM11/21/02
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On Wed, 20 Nov 2002 15:25:56 +0000, John Lansford wrote:
> I quoted:

>># Request that the need for a 250-foot right-of-way for the road be
>>re-examined so that the road is no wider than Humphreys Bouldevard,
>>which averages about 114 feet of right-of-way."
>
> A 114' R/W would have to include the following items:
>
> At least four lanes plus a 16' median, or five paved lanes. That is
> either 60' or 64' depending on the design.
>
> Curb and gutter on both sides of the road. That's an additional 4'.
>
> The berm width behind the curb. That width can range from 4' to 12',
> but if they want sidewalk they need to go with at least 8' berms.
> That's another 16' for a total of 84' if you go with the basic design.
>
> If the city wants wider lanes for bicycles (another 2' on each side)
> or parking lanes (add 8' for each side), or dedicated bicycle lanes
> (4'-8' depending on the area), you can easily run out of R/W.

Humphreys Blvd is six lanes + a raised median, for reference. No bike
lanes, but it does have curb and gutter and sidewalks.

With no driveways to naturally slow traffic, though, I think an arterial
design wouldn't be very safe, and I wouldn't expect any pedestrian or bike
traffic. (The existing road prohibits both, and there are alternate
routes for them.)

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