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Old April 10th, 2010, 12:31 AM   #101
zezi
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Croatia, D1 near Split.
Two lanes uphill, one down.
AADT about 15000


IMO 2+1 makes sense only when road is going uphill (or down ), on flat terrain it is not so good solution
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Old April 10th, 2010, 01:17 AM   #102
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Quote:
Originally Posted by niterider View Post
I think that is besides the point. Surely if you have a relatively major route, it is safer to have a physical separation between the lanes of traffic traveling in opposite direction.
Even if a person can more easily distinguish a yellow divider line, it doesn't help them if a truck veers into them from the other direction!
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Originally Posted by Spikespiegel View Post
I've never heard of any accidents here where people thought they were on their own side of the road, while in fact they were in the oncoming lanes. Usually head on collisions happen when people fall asleep behind the wheel, or are drunk, in either case, they shouldn't be driving. It's very easy to tell the difference between lane dividers and direction dividers, so there is no need to recolour them.

Also, I don't see how you would come to the conclusion that people see the 2+1 roads as dangerous. You will get plenty of warning to merge with lane one, as you approach the end of a "2" section. At the end of the "2" section is a relatively long "buffer zone" before the oncoming traffic's "2" zone starts.

2+1 roads usually have very few access roads, so you don't even have to worry about crossing traffic.

Besides, the second lane is for overtaking only. Driving in them, when you are not overtaking is forbidden, and as long as you do your overtaking before the first "merge" warning, you will never even get close to the end of the "2" zone.
I know that. I don't see what that has to do with anything, though. I never said that a yellow line makes a road impervious. I said that yellow lines make things less confusing. There is no question as to where your lane is and where oncoming traffic is supposed to be. You never have to wonder when a yellow line is used.

I agree that a separated road is always safer, but funds aren't always available. If they were, the 1x1 wouldn't exist and all roads would be separated.

Consider for a moment a straight piece of European 1x1 road. The shoulder lines are solid white and the centre line is perforated white. It is identical to a separated 2x2 stretch of road.

The same type of road in North America is the same, except that the centre line would be yellow. If ever there is a perforated white centre line, we know that it's always safe to pass because the white line only denotes a lane change amongst traffic travelling in the same direction.

My point is, a yellow centre line is safer than having it all white all the time.
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Old April 10th, 2010, 10:25 AM   #103
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It's hard to say. Often, 2+1 roads are upgrades of existing 2-lane roads, often partially on a new (better) alignment. 2+1 roads also tend to have a limited access facility, with grade-separation as much as possible, which increases the cost of course.

They have built many 2+2 roads in midwestern United States that carry less than 10,000 AADT, and also not rarely less than 5,000 AADT. Land was incredibly cheap in those areas, for example New Mexico or Indiana.

2+1 roads, however, require a significant distance before they can be useful. They don't work in roads with a lot of driveway access, slow traffic, intersections and what have you. Therefore, 2+1 roads often need to be build on a new alignment, which increases the cost because of land expropriations, acquiring a right-of-way.
I found a picture of the Danish standards for 2+2 highways vs 2+1 roads. And alone the amount of land a 2+1 road occupies is 1/3 less than the 2+2 highway, and if you do not use bridges for crossing traffic, we are way under half the price for a 2+1 vs a 2+2.

But are they the right choice for us in Denmark, I start to doubt, we have no mountains but a lot of cheep farmland.:



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Old April 10th, 2010, 10:48 AM   #104
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european E50 / slovak I/18 between cities Žilina and Martin







years ago
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Old April 10th, 2010, 10:57 AM   #105
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In Australia its moslty 1x1 between cities. However, there are 2x1 overtaking sections every 10-30 km or so. This gives motorists the opportunity to overtake safely if they are stuck behind slow vehicles.
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Old April 10th, 2010, 02:00 PM   #106
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Quote:
Originally Posted by Fender56 View Post
I found a picture of the Danish standards for 2+2 highways vs 2+1 roads. And alone the amount of land a 2+1 road occupies is 1/3 less than the 2+2 highway, and if you do not use bridges for crossing traffic, we are way under half the price for a 2+1 vs a 2+2.

But are they the right choice for us in Denmark, I start to doubt, we have no mountains but a lot of cheep farmland.:

http://img708.imageshack.us/img708/576/22vs21.jpg
Sometimes a 2+1 road can be built as one roadway for a future motorway. However, this only makes sense if the 2+1 road has the same alignment as a motorway would have.
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Old April 10th, 2010, 03:01 PM   #107
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Originally Posted by ChrisZwolle View Post
Sometimes a 2+1 road can be built as one roadway for a future motorway. However, this only makes sense if the 2+1 road has the same alignment as a motorway would have.
For comparison, i found some construction costs, to illustrate the difference, between a Danish 2+1 expressway and a 2+2 highway, both under construction.

The 9 km 2+1 expressway Bredsten-Vandel costs 384 mio dkr, or 43 mio dkr pr km.!

http://www.vejdirektoratet.dk/dokume...nt&objno=92805

The 26 km 2+2 highway Kliplev-Sønderborg costs 1.339 mio dkr, or 51,5 mio dkr pr km.!

http://www.vejdirektoratet.dk/dokume...nt&objno=86675

And that means a 2+1 expressway costs more than 80% of a fully 2+2 highway...... So i dont see why they dont build the real highway, with such a small margin.

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Old April 10th, 2010, 03:11 PM   #108
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That 2+1 road must replace route 28, and crosses a small valley. One bridge could significantly influence the price of a road, especially in this case where the road is only 9 km long. I'm not sure if this is a good comparison.
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Old April 10th, 2010, 03:49 PM   #109
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Quote:
Originally Posted by ChrisZwolle View Post
That 2+1 road must replace route 28, and crosses a small valley. One bridge could significantly influence the price of a road, especially in this case where the road is only 9 km long. I'm not sure if this is a good comparison.
Certainly those 2 bridges influences the total price, but its still a very high price. If you see the cut of the Bredsten-Vandel expressway below, you´ll see there´s no safety fences between the traffic, and there are also no emergency lanes, like on real 2+2 highways.:



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Old April 10th, 2010, 09:29 PM   #110
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In Greece, national roads 1/1a and 8a had been constructed since the late 1950's with most parts being 14m wide with 1.5+1.5 lanes. There was (and still is in the unfinished sections of A1 and A8 that replaced them) a solid line dividing the main traffic lane in each direction from the rest of the road to the right with the allowance for slower traffic to use this half lane in order to allow faster vehicles to overpass. This of course in case of two lorries has been very dangerous and has been proved by the numerous accidents on these two roads. It has also led to confusing Greek drivers about what does a hard shoulder mean after the first Greek motorways appeared (there are still a lot of @%$^*& who drive in it).

Unfortunately the same 1.5+1.5 arrangement was later used to sections of national roads 3, 9, 12 and 90 with the same problems. Only a few sections of 2+1 roads were constructed; randomly I can recall some stretches of national roads 3 (north of Lamia) and 18 (near Parga).
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Old April 11th, 2010, 01:09 PM   #111
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Same situation as Australia. Because of the total absence of proper intercity motorways, New Zealand cities and intercity highways are mainly 1+1 with 2+1 stretches at intervals for overtaking.
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Old April 11th, 2010, 01:59 PM   #112
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Aren't there any problems with winter maintenance in northern countries, such as Finland or Denmark? As far as i understand, snow on a 2+1 road without barrier is not an option. How could you know, where is your lane and where not?
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Old April 11th, 2010, 02:58 PM   #113
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I must say that I am a huge fanboy of the Swedish 2+1 roads. They are well-maintained, smooth, safe and they go through interesting landscapes (lots of forests), whereas the motorways in Sweden are very dull.
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Quote:
Originally Posted by Swedway
Sweden has build almost 2000 km of 2+1 roads. 330 km is Autostrasse and 1660 km is ordinary highways.
Is there some map or list of 2+1 roads in Sweden? Maybe on vv.se site?
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Old April 11th, 2010, 06:13 PM   #114
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Aren't there any problems with winter maintenance in northern countries, such as Finland or Denmark? As far as i understand, snow on a 2+1 road without barrier is not an option. How could you know, where is your lane and where not?
We just drive in the lane they´ve cleaned.!

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Old April 11th, 2010, 10:39 PM   #115
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Quote:
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We just drive in the lane they´ve cleaned.!

What do you mean by that? Do you drive on 2+1 like on ordinary 1+1?
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Old April 12th, 2010, 01:05 AM   #116
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Quote:
Originally Posted by Jevpls View Post
What do you mean by that? Do you drive on 2+1 like on ordinary 1+1?
Sometimes the extra lane is full of snow slush, or hasn't been plowed properly, like this:




Knowing where the lanes are is pretty easy here, since almost all 2+1 roads are divided, plus signage obviously.

Also, found this video with some 2+1 winter driving along E4 north Sweden

http://www.youtube.com/watch?v=Z4Y20UD9EdE

Last edited by metasmurf; April 12th, 2010 at 08:11 AM.
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Old April 12th, 2010, 08:24 AM   #117
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It's easy with Sweden - you SEE the barrier even if the snow hasn't been cleaned for some time. But without barrier even a little amount of snow can hide all lines...
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Old April 12th, 2010, 11:07 AM   #118
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Quote:
Originally Posted by metasmurf View Post
Also, found this video with some 2+1 winter driving along E4 north Sweden

http://www.youtube.com/watch?v=Z4Y20UD9EdE
Nice video, anyway 100-120 km/h + overtaking in this snow
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Old April 12th, 2010, 11:34 AM   #119
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As I'm collecting information about 2+1 roads, I would be grateful for some information. If it's not hard for you then, please, try to answer these questions:

1) Name your country.
2) Do 2+1 roads have safety barrier in your country?
3) AADT. What is the max. and min. value of AADT for 2+1 in your country? And what is the recommended AADT value?
4) What is the max. allowed driving speed on 2+1 roads in your country?
5) Do intersections are allowed in one level?

If it's possible then please add a picture with cross section scheme.

[If something from these questions is answered in previous pages then ignore it.]

Thanks in advance.
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Old April 12th, 2010, 12:15 PM   #120
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Aren't there any problems with winter maintenance in northern countries, such as Finland or Denmark? As far as i understand, snow on a 2+1 road without barrier is not an option. How could you know, where is your lane and where not?
First of all Denmark has very few 2+1 roads, and secondly (except for this winter) we seldomly have problems with snow on the roads (hardly anything compared with Finland) and then only for a few hours until it has either melted or been plowed away.
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