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Old February 27th, 2007, 05:43 PM   #81
Chicagoago
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^ I think people have the misconception that since these German roads don't have limits, then EVERYONE must just slam their foot on the gas pedal and not let up until they've flown off a bridge or get to their destination.

Obviously if you rationally think of it, why would a normal person be going as fast as humanly possible in their car every time they drive. People are very responsible drivers in Germany - you have to be if you want the privilege of driving as fast as you feel.

It's like drugs being tolerated in Amsterdam. People think - oh, you can do drugs and the cops won't bust you - EVERYONE must be getting high all the time. The first time I went there I asked my friend about it who's from Amsterdam, he said "no, the Dutch might smoke a joint every once in awhile to relax, as you'd go to a pub - but much of the business coffeeshops get is from tourists like yourself". Of COURSE, I was racing to a coffeeshop with him as we had this conversation.
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Old March 7th, 2007, 08:33 AM   #82
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is autobahn already an internationalism?
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Old March 7th, 2007, 10:02 AM   #83
Alex Von Königsberg
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Quote:
Originally Posted by Chicagoago View Post
^ I think people have the misconception that since these German roads don't have limits, then EVERYONE must just slam their foot on the gas pedal and not let up until they've flown off a bridge or get to their destination.

Obviously if you rationally think of it, why would a normal person be going as fast as humanly possible in their car every time they drive. People are very responsible drivers in Germany - you have to be if you want the privilege of driving as fast as you feel.
Absolutely. For most foreigners first thing that comes to mind when they hear the word "Autobahn" is "No speed limit". For me, "Autobahn = Excelent Drivers' Discipline". If I want to drive as fast as I want, I can go to Nevada and do it on I-80 in rural areas, but I-80 will not become the autobahn just because you can put the pedal to the metal there.
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Old March 7th, 2007, 12:21 PM   #84
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When I think of the autobahns (XD) I think of no speed limit, but not because I can floor my car to 180 mph, but rather have ease of mind about not having to worry about straying over the limit and be able to travel at a speed that suits me, and not have to look around every nook and cranny to see if a cop is hiding there waiting to hand me a ticket.
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Old March 15th, 2007, 10:22 PM   #85
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Originally Posted by Verso View Post
That's not some German particularity; no country is so stupid to build sharp curves, if not necessary.
Portugal is
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Old May 13th, 2008, 10:08 PM   #86
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Traffic engineering & terminology

Hi, welcome to this thread.

I'll start to explain some traffic engineering and terminology concerning road traffic.

First of all:

Terminology

There are several ways to mention a "motorway". Throughout Europe, motorway is the most used English term to refer to a motorway-grade road. In the United States and several Asian countries, the word "Expressway" is often used to mention a motorway-grade road. Some states and countries also use the word "Freeway", which, contrary to popular belief, doesn't mean free of tolls, but more to the "freeflowing situation" that occurs on those roads.

Motorway, Freeway and Expressway can all mean the same! Ofcourse, many languages have their own term to refer to the motorway. Within this forum, you'll see forumers use different terms, which apply to the area they live in.

However, an HIGHWAY does not exclusively refer to a motorway-grade road! It's a general term for (usually connecting) roads. One better use the word "motorway" and not "highway", if they refer to a motorway-grade road.

The term Expressway however, is more vague. In some countries, they can also refer to 4 lane main highways with traffic lights, or one lane highways with grade-separated junctions. The latter is usually called a Motorroad. They usually have a higher speed limit than other one lane highways.

2x3, 3+3 or 6 lanes?

This issue also is a source of confusion. Literally, they all mean the same. The correct term in many countries is: The number of lanes per direction multiplied by the number of roadways. So a motorway that carries 3 lanes per direction can be called 2x3. A motorway that carries 4 lanes per direction split over 4 separate roadways is called 4x2.

3+3 or 2+1 usually refers to a highway without central reservation or median, but not exclusively, it depends on location.

x lanes (2,4,6,8 or whatever) is usually the term in North America. 6 lanes usually means 2x3 lanes. Americans rather say the total number of lanes than the number of lanes per direction.

That also brings is to the next issue: The Roadway. A roadway is a piece of paved road which carries a certain number of lanes from median to shoulder. In other words, one roadway can carry 2,3,4 or even more lanes. A collector/distributor, or sometimes called local/express system usually carries 4 separate roadways, with a certain number of lanes per roadway.
If there is no median, there is only one roadway, carrying both directions.

Highway capacity

The capacity of a highway can be estimated. However, there is no definate concensus about how this should be done.
The most common way is to count the number of lanes, multiplied by the lane capacity per hour and multiplied by the number of representative hours.

In example a 2x2 motorway: 4 X 2200 X 10 = 88,000 AADT capacity

There are several points where there is no consensus about.
First of all, the capacity per lane. 2200 is the most used fact, however some experts also suggest 2500 or 2000 vehicles per lane per hour.
Second of all, the number of representative hours (usually 10) is subject to debate, since some also use 11 or 12 hours, which should lead into a higher capacity.

Besides that, there are a number of facts which reduce the capacity of a lane.
1) on motorways with more than 3 adjacent lanes per direction, the capacity per lane decreases, since most traffic tries to stick to the right most of the time, to exit. This increases weaving and reduces capacity
2) tunnels, bridges are capacity reducing objects. This can also occur when there are no shoulders, or limited visibility due to greenery too close to the roadway. There is no hard fact about what the capacity is at those objects.
3) Weather condition can also reduce capacity, for example in rain, people keep more distance, so the capacity is reduced. Ofcourse, some more extreme weather conditions, like hail, snow, ice and fog can reduce the capacity even further.
4) At interchange where there is a lot of entering and exiting traffic, the capacity can reduce because of weaving.
5) Some sections have long merge lanes between 2 exits which functions as a de facto 3rd of 4th (or more) lane. Such lanes cannot be counted for full capacity.
6) The amount of truck traffic is also important. When 20% - 30% on busy 2x2 motorways of the traffic are trucks, the right lane is usually completely taken by trucks. This also reduces capacity significantly.

However, in reality, congestion is starting to exist from about 70,000 to 80,000 vehicles per day on 2x2 motorways. They are able to carry more, there are motorways known that carry over 100,000 vehicles per day on 2x2 lanes.

Intensity vs Capacity
A way to measure intensity vs capacity is the I/C value, the intensity divided by capacity. We now know how to calculate the approximate capacity, and traffic volume stats are often available. This can be done properly with hourly stats, however, they are usually limited available, or only available for pros. One can get an approximate I/C value by calculating daily figures.

For instance, the US 290 in Houston. The road has 2x4 through lanes (and merging/weaving lanes between some exits), which could lead into a capacity of (2200 * 8 * 10) 176,000 to (2200 * 8 * 11,5) 202,400. The actual traffic intensity is 243,000. 243,000 / 202,400 = I/C 1.2 which is extremely high resulting into major congestion. From 0.9 - 1 one can already see congestion.

Another example, the notorious I-405 in Los Angeles near Sepulveda Pass. There are 4 lanes southbound+HOV and 5 lanes northbound, so 10 lanes in total. Let's start: (2200 * 10 * 11)=242,000. The traffic intensity is 278,000. 278,000 / 242,000 = I/C 1.15 which is also very high, but less than the US 290 in Houston.
Caltrans also publishes peak hours. For the I-405 at the same location, the hourly capacity is 22,000. The peak hour intensity is 17,400. Huh, this leads into a 0.79 I/C, no congestion at all! It's because these are 2-way figures. Rushhour is usually limited to one direction only, but there are locations where both directions are busy as hell. Therefore, the best way to calculate I/C's is per direction.

Congestion/Traffic Jams/Queue

The definition of a traffic jam is not always defined. Dutch transportation agency defines it as "traffic driving slower than 50km/h (30mph) for 2 kilometers (1.5 mile) or more". Congestion can occur almost anywhere, and can have multiple causes, such as shortage of road capacity, road (more specific: interchange) designs, accidents, weather, holidays and events. A queue is the British term, where Traffic Jam seems to be an American term.

To drivers, the technical definition doesn't matter that much, often dense or sluggish traffic is often seen as congestion, even if the delays are minor. In the perception of drivers, there is usually more congestion than in reality. Most radiostation broadcasts frequent traffic reports, especially local metropolitan radio stations in the US, or regional, commercial and public radio stations in Europe. The traffic information is often gathered by the road authority by detection in the roadway in busy area's, and police and or visual reports in less urbanized areas. Therefore, the accuracy of traffic reports can vary greatly. Some countries or metropolitan areas have full real time traffic information where other area's depend on police reports or even from motorists.

Traffic jam detection also varies by region, some roadway detections are placed at every few hundred meters, giving a very detailed and actual situation of the flow, where other regions only have detection every few kilometers, or near exits, giving a less detailed report.

to be continued.

Last edited by ChrisZwolle; June 4th, 2008 at 05:58 PM. Reason: Some stuff added
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Old May 13th, 2008, 10:21 PM   #87
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Great idea for a thread Chriszwolle. I look forward to see diferent opinions and to debate them.
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Old May 14th, 2008, 12:14 AM   #88
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Quote:
Originally Posted by Chriszwolle View Post
Terminology
Because this forum is called "Highways & Autobahns", you should include "autobahn".

Quote:
Originally Posted by Chriszwolle View Post
2x3, 3+3 or 6 lanes?
In Germany we normaly use "3+3" and we often include the hard shoulder:
3+3 -> no hard shoulder
s3+3s -> hard shoulder ("s" for "Standstreifen")
S3+3S -> hard shoulder, wide enough for changing into an (temporary) extra lane .
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Old May 14th, 2008, 12:22 AM   #89
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Quote:
Originally Posted by Chriszwolle View Post
In example a 2x4 motorway: 4 X 2200 X 10 = 88,000 AADT capacity
Both directions have to be counted.

The lane-capacity used can differ from the guidelines on freeflow a country uses.
Using 1600-1800 will end up in a more broad motorway with less congestion.
More common is 2000 - 2150. In very busy areas the multiplier of 10,5 - 11,5 is more appropriate than 10.

In case of a 2x4:
2 x 4 x 2150 x 11 = 189.200 AADT

(I use decimal comma and thousand-dot for figures)
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Old May 14th, 2008, 12:40 AM   #90
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I thought about such a thread myself. Now I see that I wasn't the only one who recognised the need for some education. Thank you for starting it.

However, I have to interfere with this one:

Quote:
Originally Posted by Chriszwolle View Post
Motorway, Freeway and Expressway all means the same! Ofcourse, many languages have their own term to refer to the motorway. Within this forum, you'll see forumers use different terms, which apply to the area they live in.
Motorway, freeway and expressway does not mean the same. Motorway is a legal status, defined by law and marked by signs. Freeway or expressway on the other hand are just ambiguous expressions for a dualled and grade-separated road.
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Old May 14th, 2008, 01:04 AM   #91
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Great idea! I was kind of confused of the terminology myself.
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Old May 14th, 2008, 11:15 AM   #92
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Quote:
Originally Posted by aswnl View Post
Both directions have to be counted.

The lane-capacity used can differ from the guidelines on freeflow a country uses.
Using 1600-1800 will end up in a more broad motorway with less congestion.
More common is 2000 - 2150. In very busy areas the multiplier of 10,5 - 11,5 is more appropriate than 10.

In case of a 2x4:
2 x 4 x 2150 x 11 = 189.200 AADT

(I use decimal comma and thousand-dot for figures)
I made a mistake, i meant 2x2

Quote:
Originally Posted by flierfy View Post
Motorway, freeway and expressway does not mean the same. Motorway is a legal status, defined by law and marked by signs. Freeway or expressway on the other hand are just ambiguous expressions for a dualled and grade-separated road.
I do not agree, since a Freeway or expressway are just a local term to mention a motorway. All Chinese motorways are called expressway for instance. (except the oldest, which were called freeways, but there are only a few of them). In Europe, the expressway is indeed usually a lower category, but this doesn't apply worldwide. However, it's often seen that expressways have the same grade as motorways, for instance in Spain since a couple of years. The distinction can still be seen between older and newer Autovía's.


Last edited by ChrisZwolle; May 14th, 2008 at 12:19 PM.
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Old May 14th, 2008, 12:21 PM   #93
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Quote:
Originally Posted by ABRob View Post
In Germany we normaly use "3+3" and we often include the hard shoulder:
3+3 -> no hard shoulder
s3+3s -> hard shoulder ("s" for "Standstreifen")
S3+3S -> hard shoulder, wide enough for changing into an (temporary) extra lane .
I think this is a typical German way, i haven't seen it elsewhere (Which doesn't mean it's impossible though).

Sometimes, you can also read " 2x3 lanes: 2 lanes per direction and emergency lanes". Technically, this is wrong since "2x3 / 3+3" only means the driving lanes, and does not include shoulders/emergency lanes.
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Old May 14th, 2008, 09:26 PM   #94
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Quote:
Originally Posted by Chriszwolle View Post
I do not agree, since a Freeway or expressway are just a local term to mention a motorway.
Not at all. Motorway is not just a road but a legal concept. Most countries in the world don't have this. And I'm curious to know whether this sign in China has any consequences:
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Old May 15th, 2008, 12:28 AM   #95
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A legal concept where? In the US (at least in certain states, like California), "freeway" is a legal concept. In fact, I don't even think "motorway" is ever used in most places in North America, including in law. I never heard of this term until coming to this forum.
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Old May 15th, 2008, 06:22 PM   #96
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Interesting thread, Chris!
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Old May 16th, 2008, 09:35 AM   #97
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Quote:
Originally Posted by TheCat View Post
I don't even think "motorway" is ever used in most places in North America
Motorway is a British term... it's not utilized in North America... no one would know what you are talking about.

It's similar to the British term "lorry". In North America, one uses the word "truck".

Expressway is mostly used in the eastern United States. Otherwise freeway is the standard terminology elsewhere.

But there is also a separate definition for "freeway standard" and "expressway standard".

Expressway standard refers to a freeway standard highway (same design standards, geometry, etc) except that some lighted intersections exist at low volume intersections, which are upgradeable to interchanges when traffic later warrants.
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Old May 16th, 2008, 04:00 PM   #98
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Quote:
Originally Posted by Chriszwolle View Post
Some states and countries also use the word "Freeway", which, contrary to popular belief, doesn't mean free of tolls, but more to the "freeflowing situation" that occurs on those roads.
In some English-speaking states/countries they indeed mean "free of toll" with "freeway". I don't remember where though.

Quote:
Originally Posted by Chriszwolle View Post
The term Expressway however, is more vague. In some countries, they can also refer to 4 lane main highways with traffic lights, or one lane highways with grade-separated junctions. The latter is usually called a Motorroad.
In Wikipedia I've seen expression "motor-route".
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Old May 16th, 2008, 04:01 PM   #99
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Wikipedia:

Quote:
The Autostrasse literally means motorroad in English and exists in some European countries, noticeably Austria, and Switzerland, and some others like Sweden, France, Slovakia, Poland, Netherlands and Norway under another name. The faster equivalent is the Autobahn (motorway). The Autostrasse can also be translated as a semi-motorway.

A similar type of road seen in North America is known as a two-lane freeway, albeit with fewer construction standards.
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Old May 16th, 2008, 05:29 PM   #100
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Interesting... but is there also an Autostrasse category in Austria, besides Schnellstrasse? I definitely saw some 2x1 sections with blue signs and a car symbol (the one for expressways). It seems it is used on some bypasses/sections with tunnels.
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