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Poll

What's the best length for a median on a freeway?

Have a concrete barrier
- 22 (37.3%)
46 (like many freeways in North Carolina)
- 5 (8.5%)
60 (Wilson bypass, US-64 east of Tarboro)
- 13 (22%)
70 (Edenton, Elizabeth City, Clayton bypasses)
- 6 (10.2%)
84 (US 264 in Sims, Bailey, Middlesex)
- 5 (8.5%)
96 (US 70 from Dover to New Bern)
- 8 (13.6%)

Total Members Voted: 40


Author Topic: What's the best median width for a freeway?  (Read 5886 times)

tolbs17

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Re: What's the best median width for a freeway?
« Reply #25 on: October 08, 2021, 08:17:00 PM »

I-84 between the CT border and MA 131 is perfect. :bigass:
How about I-85 that crosses over Hamby Creek in North Carolina?
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J N Winkler

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Re: What's the best median width for a freeway?
« Reply #26 on: October 09, 2021, 01:32:29 PM »

As a driver, I don't really feel it is possible to have a median that is too wide in rural areas.  As median width increases, the amount of glare screening and roadside safety hardware that has to be provided goes down, while the options for securing satisfactory drainage (and resiliency during high-intensity rainfall) broaden.  But there are definitely tradeoffs in terms of ROW acquisition cost, taking land out of productive use, and span lengths for overbridges and other crossing structures.

Some states, such as Oklahoma, already provide cable barrier for medians as wide as 80 ft.  I expect this practice to become more common and, for this reason, I don't think a policy of providing wide medians expressly to eliminate the need for cable barrier will survive the test of time.
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webny99

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Re: What's the best median width for a freeway?
« Reply #27 on: October 10, 2021, 10:22:14 AM »

I-490 west of Rochester is an example of a roadway that was intentionally built with a very wide median to allow for future widening that was never needed (and likely never will be, especially west of Exit 4).

It's a great road on the whole, but as I've mentioned previously, I don't like long stretches where you can't see traffic going the other direction, and it does have a few of those.
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CtrlAltDel

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Re: What's the best median width for a freeway?
« Reply #28 on: October 10, 2021, 11:39:21 AM »

My obvious preference would be for whatever is best engineeringwise for the location in question, but that's not really a fun answer. So, what I did is I went ahead and drew an Interstate highway, to scale, in Microsoft Paint, and moved the carriageways around until I found the median that looks best aesthetically, which turns out to be 40 feet, or 48 feet if you include the left shoulders, which median widths always do for some reason.

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tolbs17

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Re: What's the best median width for a freeway?
« Reply #29 on: October 10, 2021, 01:12:06 PM »

My obvious preference would be for whatever is best engineeringwise for the location in question, but that's not really a fun answer. So, what I did is I went ahead and drew an Interstate highway, to scale, in Microsoft Paint, and moved the carriageways around until I found the median that looks best aesthetically, which turns out to be 40 feet, or 48 feet if you include the left shoulders, which median widths always do for some reason.


Ikr, they couldn't just do the grass...
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jlam

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Re: What's the best median width for a freeway?
« Reply #30 on: October 10, 2021, 01:16:34 PM »

How about the one-and-a-half mile median along I-8 in Ocotillo?
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SeriesE

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Re: What's the best median width for a freeway?
« Reply #31 on: October 10, 2021, 03:16:00 PM »

As narrow as the standards permit, so standard width of the left shoulders + the width of the concrete barrier
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ran4sh

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Re: What's the best median width for a freeway?
« Reply #32 on: October 10, 2021, 11:32:00 PM »

Wide enough to have trees that block opposing headlights

Barriers that are built high enough are also effective at blocking headlights. So about 25 feet (10 foot left shoulder on each side, leaving 5 feet for the barrier itself)
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Mr Kite

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Re: What's the best median width for a freeway?
« Reply #33 on: October 21, 2021, 10:32:16 PM »

The UK pretty much always uses barriers and always has done, I think. In fact, that seems to be the done thing in most places outside North America. England current uses concrete "Jersey" barriers on medians. Until a decade or so back, metal barriers were used.
« Last Edit: October 21, 2021, 10:34:21 PM by Mr Kite »
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Road Hog

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Re: What's the best median width for a freeway?
« Reply #34 on: October 23, 2021, 02:14:00 AM »

I'm OK with a Jersey barrier anywhere if it reduces ROW costs and expedites construction. Plus, it cuts down on smokey bears camping in the median....
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Road Hog

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Re: What's the best median width for a freeway?
« Reply #35 on: October 23, 2021, 02:16:41 AM »

The UK pretty much always uses barriers and always has done, I think. In fact, that seems to be the done thing in most places outside North America. England current uses concrete "Jersey" barriers on medians. Until a decade or so back, metal barriers were used.
Older parts of the German Autobahn used simple guard rails in the 1990s. I seem to remember more permanent barriers in urban areas.
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tolbs17

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Re: What's the best median width for a freeway?
« Reply #36 on: October 23, 2021, 02:38:33 AM »

I'm OK with a Jersey barrier anywhere if it reduces ROW costs and expedites construction. Plus, it cuts down on smokey bears camping in the median....
But it's more expensive.
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tolbs17

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Re: What's the best median width for a freeway?
« Reply #37 on: January 25, 2022, 06:58:59 PM »

I forgot to mention that US-64 between Tarboro and Williamston has a series of transitioning between 46 feet and 60 feet. How cool is that?

Prior to the 1970s medians used to be very small like look at the Nashville, NC bypass (US-64)

Or I-95 between Kenly and Eastover.
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HighwayStar

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Re: What's the best median width for a freeway?
« Reply #38 on: January 25, 2022, 07:20:55 PM »

I am not a fan of the densely forested medians common on interstates in the Southeast. I find it quite tiring, even more so than traditional "boring" freeways such as I-80 or I-90 across the Plains. I think being able to see traffic heading the other direction really does help one keep awake.

If you need oncoming traffic to keep you awake you are too damn tired to be driving and belong in a motel room.
What it does, which is a real benefit, is block oncoming headlights at night. And today with the stupid arms race of LED lights and no one having heard of a dimmer switch it is far more fatiguing to be blinded all the time than not see the oncoming traffic at all.
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HighwayStar

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Re: What's the best median width for a freeway?
« Reply #39 on: January 25, 2022, 07:22:47 PM »

Wide medians are great for reserving future right of way, great if you need to add lanes or finally do the sensible thing and add service plazas to all interstates.
Also good for conversion into runways if needed.
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tolbs17

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Re: What's the best median width for a freeway?
« Reply #40 on: January 25, 2022, 07:40:48 PM »

Wide medians are great for reserving future right of way, great if you need to add lanes or finally do the sensible thing and add service plazas to all interstates.
Also good for conversion into runways if needed.
Yes, also not having to replace the bridges, like take a look at the Fayetteville bypass for instance or I-95 south of I-74.
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ran4sh

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Re: What's the best median width for a freeway?
« Reply #41 on: January 26, 2022, 05:56:46 PM »

Wide medians are great for reserving future right of way, great if you need to add lanes or finally do the sensible thing and add service plazas to all interstates.
Also good for conversion into runways if needed.

Service plazas should only be located in the median if under or over passes are provided so that traffic doesn't have to use left exits or entrances to access them.
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HighwayStar

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Re: What's the best median width for a freeway?
« Reply #42 on: January 27, 2022, 10:30:37 AM »

Wide medians are great for reserving future right of way, great if you need to add lanes or finally do the sensible thing and add service plazas to all interstates.
Also good for conversion into runways if needed.

Service plazas should only be located in the median if under or over passes are provided so that traffic doesn't have to use left exits or entrances to access them.

In a sufficiently low traffic area I don't see it as a problem. There are some in the northeast with the left ramp that should not have one, but in other areas it would be fine.
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tolbs17

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Re: What's the best median width for a freeway?
« Reply #43 on: February 02, 2022, 12:30:42 PM »

As seen in pages 22, 23, and 24 for North Carolina, 70 feet is usually preferred for new locations unless there's a protected area. 60 feet is for no future lanes required. Lastly 46 is for areas with protected areas such as wetlands, districts, etc.

Which is funny because I-40 was built with a 46 feet median between Clayton and Wilmington as well as between Hillsborough and Durham. Now it's overpopulated and needs many more lanes.

https://connect.ncdot.gov/projects/roadway/roadway%20design%20manual/01.%20general%20design.pdf
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