What constitutes a median or divider?

[roadman65]

Take a look here on the link of a section of PA 309 near Wilkes Barre, PA that is considered a divided roadway on most maps, but if you look there is just a strip of concrete in the middle of the  center yellow lines.  I know many PA highways have this set up, and for the most part it was  created for contrast purposes more than safety, obviously.   The divider is not even a raised curb, but just enough for your eye to catch and for headlight reflection at night where as the rest of the pavement would not reflect (although there used to be concrete highways with this center strip at one time).

Would anyone say that this is a divider or just a simple undivided highway with a white strip in the middle of the center lines?

http://maps.google.com/maps?q=Plains,+PA&hl=en&ll=41.205845,-75.89628&spn=0.004205,0.010568&sll=37.0625,-95.677068&sspn=35.957999,86.572266&oq=plains,+&t=h&hnear=Plains,+Luzerne,+Pennsylvania&z=17&layer=c&cbll=41.20599,-75.896342&panoid=WqQtq0H9YYjYv0t9ReFzgw&cbp=12,194.17,,0,0

[mukade]

On a similar vein, would a continuous left turn lane on a rural highway be divided? Google map near Daleville, IN. INDOT shows this as divided.

[hobsini2]

I would say technically the one in the middle of PA 309 is a divided highway because it is curbed. The IN 67 example however is not a divided highway because there is not break in the pavement.

[NE2]

For what purposes? Passing a school bus? Interstate standards? Drainage? Capacity? You'll get different answers depending on what you're doing with the road.

[Beltway]

I would consider a highway to be divided if there is a lane or divider that is wide enough to store a left-turning vehicle, or if a narrower divider has a positive barrier such as a concrete or guardrail median barrier at least 30 inches high.

That segment of PA-309 has neither.

[3467]

http://abetter54.com/54.html

Missouri considers this to be divided

[roadfro]

The MUTCD defines a median as follows:

Median–the area between two roadways of a divided highway measured from edge of traveled way to edge of traveled way. The median excludes turn lanes. The median width might be different between intersections, interchanges, and at opposite approaches of the same intersection.

Interestingly, "divided highway" is not defined in the introduction list of definitions. The inference I get is that a divided highway has some physical object dividing or separating two adjacent roadways or paths of travel. So a concrete splitter island or curb, no matter how narrow, would be a median that creates a divided highway. This seems consistent with how GoogleMaps interprets major streets.

So in the examples of above posts:
*PA 309 is a divided highway, due to the concrete splitter island (despite the insignificance of how little the concrete protrudes above the road surface.
*IN 67 is not a divided highway, as the only separation is a two-way left turn lane.

[DaBigE]

The MUTCD defines a median as follows:

Median–the area between two roadways of a divided highway measured from edge of traveled way to edge of traveled way. The median excludes turn lanes. The median width might be different between intersections, interchanges, and at opposite approaches of the same intersection.

Interestingly, "divided highway" is not defined in the introduction list of definitions. The inference I get is that a divided highway has some physical object dividing or separating two adjacent roadways or paths of travel. So a concrete splitter island or curb, no matter how narrow, would be a median that creates a divided highway. This seems consistent with how GoogleMaps interprets major streets.

I'm not surprised that there is no formal definition in the MUTCD, as a median/divider (with the exception of a painted median) would be more of a geometric design feature, not necessarily a traffic control device (sign, signal, or marking).  The AASHTO "Green Book" or Roadside Design Manual would be a better place to look for a formal definition.  If I can remember to, I'll check them when I get back to the office tomorrow.

At least in our area design lingo, a divider would typically be a Jersey barrier, thin curb head, cable system or double-sided guard rail.  A median would be anything significantly wider (4+ feet)--curbed or not.

Take a look here on the link of a section of PA 309 near Wilkes Barre, PA that is considered a divided roadway on most maps, but if you look there is just a strip of concrete in the middle of the  center yellow lines.  I know many PA highways have this set up, and for the most part it was  created for contrast purposes more than safety, obviously.   The divider is not even a raised curb, but just enough for your eye to catch and for headlight reflection at night where as the rest of the pavement would not reflect (although there used to be concrete highways with this center strip at one time).

Would anyone say that this is a divider or just a simple undivided highway with a white strip in the middle of the center lines?

http://maps.google.com/maps?q=Plains,+PA&hl=en&ll=41.205845,-75.89628&spn=0.004205,0.010568&sll=37.0625,-95.677068&sspn=35.957999,86.572266&oq=plains,+&t=h&hnear=Plains,+Luzerne,+Pennsylvania&z=17&layer=c&cbll=41.20599,-75.896342&panoid=WqQtq0H9YYjYv0t9ReFzgw&cbp=12,194.17,,0,0

If it's mountable/traversable, I would say undivided highway.  Not-mountable = divided highway.

[Beltway]

From a practical standpoint, a highway is divided if there is a lane or divider that is wide enough to store a left-turning vehicle, or if a narrower divider has a positive barrier such as a concrete or guardrail median barrier.

Anything less than that, from a practical standpoint, is an undivided highway.

[roadfro]

From a practical standpoint, a highway is divided if there is a lane or divider that is wide enough to store a left-turning vehicle, or if a narrower divider has a positive barrier such as a concrete or guardrail median barrier.

Anything less than that, from a practical standpoint, is an undivided highway.

I'd have to disagree with any definition of 'divided highway' that would count a two-way left turn lane as a "divider". A divider, from a truly practical standpoint, splits or *divides* traffic in such a way that does not allow traffic to easily cross from one roadway to the other...a TWLTL does not do that.

[Beltway]

From a practical standpoint, a highway is divided if there is a lane or divider that is wide enough to store a left-turning vehicle, or if a narrower divider has a positive barrier such as a concrete or guardrail median barrier.

Anything less than that, from a practical standpoint, is an undivided highway.

I'd have to disagree with any definition of 'divided highway' that would count a two-way left turn lane as a "divider". A divider, from a truly practical standpoint, splits or *divides* traffic in such a way that does not allow traffic to easily cross from one roadway to the other...a TWLTL does not do that.

If that is the case, a 12-foot-wide grass median does not provide a divided highway, as it would allow traffic to easily cross from one roadway to the other.

I would disagree.  It would be a narrow median, but a median nontheless.  Same for a 12-foot-wide continuous turn lane.

[NE2]

On the other hand, a median usually (a) restricts where you can legally turn left and (b) provides a safe place for pedestrians to wait. A center turn lane does neither. As I said, there's no one-size-fits-all definition.

[Beltway]

On the other hand, a median usually (a) restricts where you can legally turn left and (b) provides a safe place for pedestrians to wait. A center turn lane does neither. As I said, there's no one-size-fits-all definition.

On a rural highway those points are usually moot on the great majority of the length of the highway.

On an urban arterial the continuous turn lane can provide better access to properties, and traffic signals can obviate the need for a pedestrian to wait in the middle.

[NE2]

Which has what to do with whether it has a median or not?

[Beltway]

Which has what to do with whether it has a median or not?

It has to do with whether the road is considered a divided highway.  I wouldn't consider a road like that to be an undivided highway.  Of course, YMMV...

On the other hand, a road with a 4-foot-wide separater that has a mountable curb, I would consider to be an undivided highway.  Left turns would have to stop in the left lane until opposing traffic cleared.

[kphoger]

So I guess this is all up to interpretation, so I'll just put in my two bits.

I would consider a divided highway to have EITHER of the following between directions of transit:
(a) A physical barrier such as curb lines or a Jersey barrier,
(b) Unpaved neutral space of any width,
(c) Paved neutral space of at least one full lane's width not intended for (and striped to discourage) vehicular traffic.

For the purpose of the law, however, (c) does not qualify as two roadways but as one.

Furthermore, what happens in the following case?
Say a highway is paved with about one meter of paved neutral space, just wide enough for a physical barrier.  Down the middle runs a physical barrier, except for a five-mile-long segment where it's just two yellow lines separated by one meter of pavement.  The distance between directions of transit doesn't change, the highway design characteristics are otherwise the same, it's just missing a barrier.  Is it still a divided highway?

[Beltway]

So I guess this is all up to interpretation, so I'll just put in my two bits.

I would consider a divided highway to have EITHER of the following between directions of transit:
(a) A physical barrier such as curb lines or a Jersey barrier,
(b) Unpaved neutral space of any width,

That would include the standard double yellow lines 12 inches apart, on an undivided highway.

(c) Paved neutral space of at least one full lane's width not intended for (and striped to discourage) vehicular traffic.

For the purpose of the law, however, (c) does not qualify as two roadways but as one.

Physically one, but functionally two.

Furthermore, what happens in the following case?
Say a highway is paved with about one meter of paved neutral space, just wide enough for a physical barrier.  Down the middle runs a physical barrier, except for a five-mile-long segment where it's just two yellow lines separated by one meter of pavement.  The distance between directions of transit doesn't change, the highway design characteristics are otherwise the same, it's just missing a barrier.  Is it still a divided highway?

A positive median barrier makes it impossible to cross, so that would indeed be a divided highway, even if it is only 2 feet of median.

The Surekill Expressway is a divided highway.  If the median barrier was removed, it would be an undivided highway, IMHO.  Only 4 feet between the two roadways.

[kphoger]

I would consider a divided highway to have EITHER of the following between directions of transit:
(a) A physical barrier such as curb lines or a Jersey barrier,
(b) Unpaved neutral space of any width,

That would include the standard double yellow lines 12 inches apart, on an undivided highway.
[/quote]

Only if those twelve inches of road are not paved between the yellow lines, which I've never seen.

[mightyace]

Take a look here on the link of a section of PA 309 near Wilkes Barre, PA that is considered a divided roadway on most maps, but if you look there is just a strip of concrete in the middle of the  center yellow lines.  I know many PA highways have this set up, and for the most part it was  created for contrast purposes more than safety, obviously.  

In my youth, I've been down many roads like this including this section of PA 309.  What happened is that the concrete in the middle actually was a divider at one time and the layers of pavement have reduced it to what you see here.

[roadfro]

On the other hand, a road with a 4-foot-wide separater that has a mountable curb, I would consider to be an undivided highway.  Left turns would have to stop in the left lane until opposing traffic cleared.

You're saying a positive (although mountable) curb--thus a positive and physical barrier--would be considered an undivided highway? But a TWLTL--a simple non-positive division--makes a road a divided highway? This doesn't make any sense...

So I guess this is all up to interpretation, so I'll just put in my two bits.

I would consider a divided highway to have EITHER of the following between directions of transit:
(a) A physical barrier such as curb lines or a Jersey barrier,
(b) Unpaved neutral space of any width,

That would include the standard double yellow lines 12 inches apart, on an undivided highway.

I agree with the definitions (a) and (b). "Neutral space" would not be considered the space between double solid yellow lines, as that is operationally meant to be a single line but is drawn as two for recognition purposes.

Furthermore, what happens in the following case?
Say a highway is paved with about one meter of paved neutral space, just wide enough for a physical barrier.  Down the middle runs a physical barrier, except for a five-mile-long segment where it's just two yellow lines separated by one meter of pavement.  The distance between directions of transit doesn't change, the highway design characteristics are otherwise the same, it's just missing a barrier.  Is it still a divided highway?

The portion missing a barrier would be an undivided highway, even though all other design characteristics remain the same.

[Beltway]

On the other hand, a road with a 4-foot-wide separater that has a mountable curb, I would consider to be an undivided highway.  Left turns would have to stop in the left lane until opposing traffic cleared.

You're saying a positive (although mountable) curb--thus a positive and physical barrier--would be considered an undivided highway? But a TWLTL--a simple non-positive division--makes a road a divided highway? This doesn't make any sense...

A 4-foot-wide mountable curb island is not a "positive and physical barrier", it effectively is no barrier at all.

[kphoger]

On the other hand, a road with a 4-foot-wide separater that has a mountable curb, I would consider to be an undivided highway.  Left turns would have to stop in the left lane until opposing traffic cleared.

You're saying a positive (although mountable) curb--thus a positive and physical barrier--would be considered an undivided highway? But a TWLTL--a simple non-positive division--makes a road a divided highway? This doesn't make any sense...

A 4-foot-wide mountable curb island is not a "positive and physical barrier", it effectively is no barrier at all.

Until now, I missed the 4-foot part.  A 4-foot mountable curb island is not wide enough to store a left-turning or broken-down vehicle, whereas a TWLTL does have that capacity.

But I would still say that a TWLTL does not truly divide traffic, as opposing traffic can legally share the same space.

[Beltway]

A 4-foot-wide mountable curb island is not a "positive and physical barrier", it effectively is no barrier at all.

Until now, I missed the 4-foot part.  A 4-foot mountable curb island is not wide enough to store a left-turning or broken-down vehicle, whereas a TWLTL does have that capacity.

But I would still say that a TWLTL does not truly divide traffic, as opposing traffic can legally share the same space.

Well no ... it is not an active lane, and if a vehicle is stopped waiting to turn, an opposing vehicle has no legal grounds to occupy the same space of the stopped vehicle.

[kphoger]

OK, I didn't mean the exact same square foot.  Physically speaking, it's impossible for two vehicles to share the same space.  What I mean is that it is both legal and practicable for both directions to enter the same lane at the same time, which is exactly what the term 'divided highway' implies cannot happen.

[Kacie Jane]

Not only that, but say there's a northbound car in the TWLTL, waiting to turn left.  There's exactly as much division between that car and opposing southbound traffic as there would be on any undivided road -- yellow lines painted on the ground.