Extremely Wide Medians:

[DJStephens]

Opposite above (hence the separate post), I think exceptionally-wide medians, like Pena Blvd (Denver's airport freeway -- below) are just silly. A solid concrete barrier with a little bit of room for error is all you need.

For whatever it's worth, I don't like inside shoulders. I think it promotes stopping in the central reservation. Doing so can make it harder for emergency vehicles to get to your location. Exceptions to that being freeways with HOV/express lanes.

From the standpoint of injury risk, it is better to have an errant vehicle come to rest without hitting anything than for it to be intercepted by a barrier.  Medians of 60 feet or more essentially remove the economic case for even low-cost cable barrier.  Wide medians also greatly mitigate headlamp glare and afford more flexibility in handling drainage.

In the early 1960's, when large-scale motorway construction was just getting under way, the British investigated the possibility of providing vegetated medians but found that, owing to the high cost of land even in rural areas, this was nearly as expensive as providing an added lane in each direction.

Interstate standards call for 12 ft shoulders on both sides for facilities that handle heavy truck traffic, as opposed to the default 4 ft left/10 ft right.  One reason for this is added room to respond when trucks have to make emergency maneuvers.

Someone should have schooled Pete Rahn and Gary Johnson on that - in the mid to late nineties.  They approved two four lane projects - NM 44/US 550 and US 70, both of which had simply painted medians of roughly 3 or 4 feet.  Speeds increased, as well as head-ons and Jack-knives, and the resulting death toll from them.  There was another wreck in Cuba, NM (44/550) the other day, a freightliner crossed the center line, and impacted an SUV carrying four occupants.   All the SUV passengers, dead, as well as the driver of the Freightliner.  The Freightliner driver was drunk.  A vegetated median, of the standard 88 feet, or greater, would have likely captured the Freightliner from crossing into oncoming traffic.   Can a state DOT be sued - for poor design, in a case such as this??   

[jakeroot]

The I-55/I-44 ramps to/from Lafayette Ave in St Louis have a pretty tight median for a short stretch: https://goo.gl/iAMOSz

[Tonytone]

These are normal around these parts, Here's some examples. 
https://www.google.com/maps/@39.6708394,-75.598977,3a,66.8y,9.47h,82.65t/data=!3m4!1e1!3m2!1sjdsanxQw74OqQCu2QzpT_A!2e0

https://www.google.com/maps/@39.5812631,-75.658203,3a,66.8y,9.47h,82.65t/data=!3m4!1e1!3m2!1s0k3AyFhScfLaUIqx8UDo1g!2e0

https://www.google.com/maps/@39.4975871,-75.6458275,3a,92y,219.74h,71.64t/data=!3m4!1e1!3m2!1s_D3-BTG3T_jrY2ApurAklQ!2e0

[SSOWorld]

https://www.google.com/maps/@34.8060268,-111.6136552,14.25z

Sections of I-17 sport fairly wide medians.

[cwf1701]

One not mentioned yet, I-75 in Reading-Lockland Ohio. there is a town in the median of I-75 near Cincinnati and the NB lanes was relocated in the early 60s resulting in the wide median.

[In_Correct]

Watching Big Rig Travels, I notice that any mountain land in the east, and just about anything in the West, in the U.S.A., goes crazy when building dual carriage ways. At first, these roads are only a single carriage way with oncoming traffic or two way traffic. Then they add lanes called "Super 2" lanes. When fully upgraded, this carriageway is now a 3 laned with shoulders and the extra lane appears to be useful for trucks that struggle to climb hills.

But when they add the second carriageway, they have an extremely width between the two carriageways. This includes interesting things such as trees, rocks, and even mountains between the two carriage ways. Some times they build the second carriage way at a completely different elevation. It is sometimes higher than the original road, and sometimes it is lower than the original road. I imagine that it was very easy for them to build Interstate Highways in these areas because it looks like the land isn't even used. And now as a result, there is a huge median with plenty of nature between the two carriage ways, that I would think be preserved for ever. I actually prefer this extreme median, but at the same time I also prefer a Concrete Wall between the two carriage ways if the extreme median is not possible. Sometimes have a concrete barriers in the mountain areas. They often have concrete barriers in narrow areas (Gainesville, Texas) and in urban areas and is usually pointless to have medians because they are going to remove them and replace them with concrete barriers and sometimes additional lanes.

When I build cities with SimCity 2000, The roads in SimCity 2000 are always striped with white dotted lines but the only way to add boulevards is to add trees in between the two carriageways. (or small parks, which ends up looking like a grass median). The only way to grade separate rail is to build a "Subway To Rail Connection" going under the carriageways. Otherwise there is a constant elevated 4 lane highway option which goes over everything and has concrete barriers in the middle. I like to add frontage roads next to these. SimCity 3000 has the same highway but is now normally enclosed with walls and has much longer ramps. The regular roads are now striped with dual gold or yellow solid lines and this time you can place two of said roads next to each other and it will become a Boulevard (called Avenue) with trees in the middle. However, the carriageways do not change to a white dotted line or even yellow dotted line. They remain solid yellow and the visible traffic will drive in both directions on both carriageways, basically two two laned two way traffic roads next to each other with trees in the middle. Sim City 4 has improved boulevards and rail and grade separations.

There are other newly built highways such as U.S. 35 that have an "average" width. They do not have wide medians and if they decide to add lanes to it, they will most likely just build the lanes on the median and add a barrier or guard rail in between the carriage ways. Texas has been building carriageways with wide medians that eventually become frontage roads. There is plenty of room to build main carriage ways WITH another median. But if a city in mountain areas (or otherwise very open areas where they have giant medians), they will most likely keep the entire median and have to build frontage roads outside of the existing carriage ways.

I guess I don't understand the point of having medians when they are going to remove them anyways but it would be interesting if they build highways with 3 lane frontage road, 5 lane carriage way, huge median with forest in it, 5 lane carriage way, and 3 lane frontage road. Basically a combination of North Carolina (?) Interstates with Texas Interstates.

I looked again and SimCity 2000 has 6 lane elevated highways, not 4.

Also, I was able to build a reinforced highway bridge for the first time. The highway bridges are truss bridges while the frontage road bridges are cable stayed. But both are red. So far the rail bridges over water appear to be the same design.

[J N Winkler]

Someone should have schooled Pete Rahn and Gary Johnson on that - in the mid to late nineties.  They approved two four lane projects - NM 44/US 550 and US 70, both of which had simply painted medians of roughly 3 or 4 feet.  Speeds increased, as well as head-ons and Jack-knives, and the resulting death toll from them.  There was another wreck in Cuba, NM (44/550) the other day, a freightliner crossed the center line, and impacted an SUV carrying four occupants.   All the SUV passengers, dead, as well as the driver of the Freightliner.  The Freightliner driver was drunk.  A vegetated median, of the standard 88 feet, or greater, would have likely captured the Freightliner from crossing into oncoming traffic.   Can a state DOT be sued - for poor design, in a case such as this??

I remember the NM 44 project ("Four Lanes to the Four Corners") well from the late nineties.  The stated goal was to do in two years, with innovative finance, what would have taken 27 years using what were then the normal programming methods.  The four-lane undivided rural arterial cross-section on top of the existing alignment was sort of handwaved away as a necessary compromise to reach that goal.  Because its width and lane count were simply increased without any upgrades to the geometry, the road has horizontal curves that feel too sharp at 70 MPH as well as numerous blind summits with 65 MPH advisories (NMSHTD used to have, and NMDOT may still have, special symbolic warning signs for these).  I believe these factors, as well as the too-narrow central mall, have contributed to its deplorable safety record.

Later on NMSHTD/NMDOT suddenly "discovered" the capability to widen long lengths of US 87, US 54, US 82, US 285, US 70, etc. to a proper four-lane divided cross-section with a true 70 MPH design speed.

As regards the Hondo Valley segment of US 70, my understanding is that was a compromise to accommodate the narrow valley alignment.  There is an unexpected and very sharp curve where it climbs out of the valley toward Roswell that I think must be a bad accident black spot.

[MikeTheActuary]

So, no one's mentioned I-24 near Monteagle, TN?

https://goo.gl/maps/FFAVbW9WH7s

1.75 miles wide....

[Tonytone]

So, no one's mentioned I-24 near Monteagle, TN?

https://goo.gl/maps/FFAVbW9WH7s

1.75 miles wide....

I wonder why they didnt just cut thru the mountain instead of making the hard curve, they already dug thru half the moutain.... Finish the rest! 

[tolbs17]

Pretty much any highway built in the 70s, you can see all of these.

US-264 between Middlesex and Bailey. It's 1,000 feet (300 meters) wide. Which Turkey Creek passes under. It's a scenic byway.

https://www.google.com/maps/@35.7959385,-78.173617,1210m/data=!3m1!1e3

[Dirt Roads]

On I-79 in West Virginia, there's a creek in median almost the entire distance between Wallback (Exit 34) and Big Otter (exit 40).  And it's not all the same creek, as adjacent hollows (pronounced hollers) dump Cookman Fork heading [westbound] and Boggs Fork (heading eastbound) into the median just a quarter mile from each other.  At it's widest, it looks like right at 500 feet between the centerlines of each lane (roughly 450-foot median).

[HighwayStar]

In Montana there are at least 2 instances of rivers being in the median

https://www.google.com/maps/@47.293523,-115.1461587,3a,75y,334.9h,76.81t/data=!3m7!1e1!3m5!1swlypjkPQl2Rlb6RL_emT5g!2e0!6shttps:%2F%2Fstreetviewpixels-pa.googleapis.com%2Fv1%2Fthumbnail%3Fpanoid%3DwlypjkPQl2Rlb6RL_emT5g%26cb_client%3Dmaps_sv.tactile.gps%26w%3D203%26h%3D100%26yaw%3D99.73118%26pitch%3D0%26thumbfov%3D100!7i16384!8i8192

https://www.google.com/maps/@46.2375684,-112.1620777,3a,80.7y,43.27h,73.75t/data=!3m7!1e1!3m5!1syZsnA5qiciqe6LvyvkLSXw!2e0!6shttps:%2F%2Fstreetviewpixels-pa.googleapis.com%2Fv1%2Fthumbnail%3Fpanoid%3DyZsnA5qiciqe6LvyvkLSXw%26cb_client%3Dmaps_sv.tactile.gps%26w%3D203%26h%3D100%26yaw%3D346.66858%26pitch%3D0%26thumbfov%3D100!7i16384!8i8192

As well as one house located in the median

https://www.google.com/maps/@45.6628689,-110.6711411,3a,75y,351.45h,85.78t/data=!3m6!1e1!3m4!1swHwNb7ri-VLQ3S1EvC4ihg!2e0!7i16384!8i8192

These extreme examples aside, wide medians are desirable in most cases, particularly urban, suburban, or exurban areas where they reserve additional space for adding lanes and hopefully service plazas one day. Particularly in suburban and rural areas they also increase the effectiveness of the highway as a barrier (for example, between residential and industrial areas).

[thspfc]

This one in New Orleans has an unusually wide median for an urban street: https://www.google.com/maps/@29.8961723,-90.1371321,3a,75y,103.67h,82.22t/data=!3m7!1e1!3m5!1svokVHHIDEghbbL5SMgXjpg!2e0!6shttps:%2F%2Fstreetviewpixels-pa.googleapis.com%2Fv1%2Fthumbnail%3Fpanoid%3DvokVHHIDEghbbL5SMgXjpg%26cb_client%3Dmaps_sv.tactile.gps%26w%3D203%26h%3D100%26yaw%3D346.6732%26pitch%3D0%26thumbfov%3D100!7i16384!8i8192

[vdeane]

This one in New Orleans has an unusually wide median for an urban street: https://www.google.com/maps/@29.8961723,-90.1371321,3a,75y,103.67h,82.22t/data=!3m7!1e1!3m5!1svokVHHIDEghbbL5SMgXjpg!2e0!6shttps:%2F%2Fstreetviewpixels-pa.googleapis.com%2Fv1%2Fthumbnail%3Fpanoid%3DvokVHHIDEghbbL5SMgXjpg%26cb_client%3Dmaps_sv.tactile.gps%26w%3D203%26h%3D100%26yaw%3D346.6732%26pitch%3D0%26thumbfov%3D100!7i16384!8i8192

Isn't that supposed to become part of I-49?

[tolbs17]

Also in my thoughts, highways built before 1965 have medians that are too narrow??!!!

[plain]

This one in New Orleans has an unusually wide median for an urban street: https://www.google.com/maps/@29.8961723,-90.1371321,3a,75y,103.67h,82.22t/data=!3m7!1e1!3m5!1svokVHHIDEghbbL5SMgXjpg!2e0!6shttps:%2F%2Fstreetviewpixels-pa.googleapis.com%2Fv1%2Fthumbnail%3Fpanoid%3DvokVHHIDEghbbL5SMgXjpg%26cb_client%3Dmaps_sv.tactile.gps%26w%3D203%26h%3D100%26yaw%3D346.6732%26pitch%3D0%26thumbfov%3D100!7i16384!8i8192

Isn't that supposed to become part of I-49?

I believe so.

Even if it wasn't, there's plenty of room to extend the freeway portion of the Westbank if they wanted to. That's actually a great design there; it's basically 2 one-way streets with no development in between them.

[Dirt Roads]

Gee, I missed this one on the West Virginia Turnpike.  The split around Beaver Creek southeast of the I-64 interchange is about 1335 feet between centerlines.

[Big John]

One controversial one is Monumental Axis in Brasilia.  Some call it the world's widest road with a 250-meter median, though it acta like 2 separate one-way roads.