Types of road junctions. The most unusual road junctions

23.03.2021

transport interchange

Difficult interchange near Barcelona (Spain)

Transport interchange- a complex of road structures (bridges, tunnels, roads) designed to minimize the intersection of traffic flows and, as a result, to increase the capacity of roads. Mostly, interchanges mean traffic intersections at different levels, but the term is also used for special cases of traffic intersections at the same level.

The term is more often used in relation to complexes for one particular type of transport. In Russia, the most famous are road junctions located in Moscow (MKAD, Garden Ring, Third Transport Ring, etc.), as well as railway junctions.

Terms

Note. The article describes the terms for right-hand traffic. In the case of the left-hand side, the principle remains the same, only it is necessary to replace the left / right. This does not exclude sections with traffic in the other direction, as on Zvezdny Boulevard.

Types of traffic lights

traffic light

It is formed by crossing at an arbitrary angle (usually right) two or more roads. The term "interchange" is used only when there is a complex traffic light cycle, the presence of other roads for turning traffic, or the prohibition of following in one of the directions.

Advantages

Ease of traffic light cycles
Ability to allocate a separate cycle for pedestrians

Flaws

Left turn problem with heavy traffic on one of the roads
With heavy traffic, the waiting time for green light can reach 10 minutes (For example, earlier on Kudrinskaya Square)
With heavy traffic, there is a high risk of traffic jams

Traffic light with a pocket for a U-turn and a left turn

Such a decoupling is arranged in cases where one of the streets already has a division of flows.

Advantages

Ease of traffic light cycles.
The existing space at the old intersection is being used.

Flaws

Overloading a road with pockets can create traffic jams. For example, in the area of \u200b\u200bthe Profsoyuznaya terminal station, public transport after disembarking does not have time to immediately change lanes into 3 lanes, which leads to confusion
When turning left (and sometimes when turning), you must stand on at least two "reds" (to solve this problem, a right turn on red is usually allowed).
The situation of pedestrians is deteriorating due to the reduction of the cycle or the elimination of a virtually traffic-free crossing. Such an interchange is often built in conjunction with an underpass.
It is necessary to remove obstacles to the visibility of pedestrians, or there is a danger of a right turn.

Circular

It is based on the fact that instead of an intersection, a circle is being built, on which you can enter and exit anywhere.

Advantages

The number of traffic light cycles is reduced to a minimum of two (for a pedestrian crossing and the passage of cars), sometimes traffic lights are abolished altogether
No left turn problem (when driving right)
Possible branch and more than four roads

Flaws

Cannot give priority to any (main) road; It is used, as a rule, on roads of similar congestion.
High emergency hazard
The need to clearly consider the flow of pedestrians
Requires a lot of extra space
Bandwidth limited by circumference
No more than 3 lanes

Atypical solutions

K-element

One of the roads necessarily consists of three segments, two of which are roads for movement each in their own direction, and the third is a dedicated lane, while at the intersection the central lane “changes” from one side. There are also special cases of leaving the selected lane to a secondary road (Vavilova Street) with the allocation of a boulevard (Nakhimovsky Prospekt)

Advantages

Dedicated cycle for OT is combined with a left turn of two lanes
The left turn passes with a delayed turn further through the central lane

Flaws

It is necessary to take into account the structure of the surrounding streets

Types of interchanges for crossing a highway and a secondary road

Parclo (Incomplete Deployment)

An example of a "half daisy"

Or partial clover. Popular in Moscow. There, the most striking example is interchanges near the Kuntsevskaya metro station or at the entrance to Reutov/Ivanovskoye.

Advantages

More speed than typical clover due to longer stripes
Cheaper by building shorter bridges
All areas involved
Often designed specifically for the predominance of the left turn

Flaws:

Only a part of the lanes for the exit / exit is allocated. It is not possible to select all bands.
U-turn from a secondary road is impossible in principle.

Traffic lights and tunnel

On the main road, a tunnel (or overpass) is being built for traffic straight ahead, for the rest, traffic lights are kept

Advantages

Allows you to highlight the dominant flow without compromising the secondary road
Virtually no barriers to public transport
It is often possible to make the upper zone predominantly pedestrian (example - Triumfalnaya Square in Moscow)

Flaws

The predominance of one of the streams over the other is necessary. If the flows are compared, then it becomes impossible for public transport to move through the traffic light zone (for example, on Mosfilmovskaya Street), with an increase in flow, the tunnel may also become clogged
Need more distance before next intersection compared to traffic lights

Roundabout with highlighting of the forward direction

Advantages:

compactness
Simple reversal on the ring
Possibility of rebuilding from the roundabout

Flaws:

The speed of movement on the ring is limited by its size.
Thread conflict on the ring can lead to congestion

diamond-shaped

At the approaches to the junction, the roads branch into right and left turns; the crossing of streams is bred by a bridge. Inside the rhombus formed by roads for left turns, a direct intersection is built as a branch from them; at the same time, the direction of movement changes (right-hand becomes left-hand).

Advantages:

High throughput and speed of movement;
Left turns have the same large radius as right turns;
There are no warring flows (entry after exit);
The left turn is intuitive.

Flaws:

It is necessary to build 5 bridges;
In the basic configuration, a turn is not possible.

Types of traffic light interchanges for highway junction

tubular

Two-level junction, one of the left turns is made as a right 270 degrees. U-turn in the basic configuration is not possible. During construction, the interchange requires the construction of only one direct intersection. This interchange is most popular, in particular, on the Moscow Ring Road.

T-shaped

In a T-junction, left turns are made at separate levels using

Semi-clover

A two-level interchange in which both left turns are made as right 270 degrees. In the basic configuration, a U-turn on an adjoining road is possible. There may be a conflict of flows inherent in a clover interchange due to the location of the entrance before the exit. During construction, the interchange requires the construction of only one direct intersection; when the road is extended, it is possible to complete the construction to the clover.

Promising Interchange Projects

Interchange Petruk

Near the Shulyavska metro station in Kiev there is a semi-clover interchange, which is extremely inconvenient for both motorists and pedestrians. From two corners of the four - buildings. After a nearby market burned down in 2007 and doubts arose about the reliability of the bridge, projects to rebuild such a difficult interchange followed. One of them was proposed by the Ukrainian engineer Viktor Petruk.

The Petruk interchange can be considered as a compromise implementation of the accumulative interchange, in which the left turns are not separated in height, but are on the same level, thus forming conflicting pairs of flows. A feature of the interchange is the organization of traffic on the ring part clockwise (for right-hand traffic). For example, the trajectory of the left turn is shown in the diagram with a green arrow.

Advantages

It is compact, implementation in dense building is possible.
Relatively easy to build.
Intuitive organization of turns. To go left you have to turn left, to go right you have to turn right. When driving, you must give way to the obstacle on the right.
Easy turn in basic configuration.
Fewer conflicting flows compared to a roundabout with direct passages at a comparable cost and similar design.
Entry after exit.

Flaws

Four intersections of perpendicular flows compared to their absence at the "clover" or cumulative interchange - for intersecting pairs of left turns.
The roundabout is organized non-standard, clockwise (for right-hand traffic)
For the movement of pedestrians, the organization of a separate "pedestrian" level is required.
Low speed on left turns and U-turns.

Big Encyclopedic Dictionary

A complex of structures at the intersection of roads of two or more directions for turning vehicles from one direction to another. Interchanges are arranged mainly in two (for example, "cloverleaf") or several levels. * … encyclopedic Dictionary

The connection of highways (See Automobile road) at different levels with exits for the passage of cars and other vehicles from one road to another. T. r. arrange on highways of the 1st, 2nd, 3rd categories. ... ... Great Soviet Encyclopedia

A complex of structures at the intersection of roads of several directions for turning transport from one direction to another. T. r. suit in one or several. levels. In system T. r. includes the arts. embankment structures, excavations, overpasses, tunnels. ... ... Big encyclopedic polytechnic dictionary

A structure (or complex of structures) at an intersection of roads that ensures the uninterrupted movement of traffic flows in various directions. Arranged in two or more levels. If the interchange scheme provides continuous ... ... Construction dictionary

1st class transport interchange- full multi-level decoupling with maximum parameters; is designed at the intersections of the main streets of citywide significance of class I...

Reading 4 min. Views 3.3k. Posted on June 25, 2014

Traffic jams are the curse of any modern metropolis. In order to save time for city residents and distribute traffic flows, design engineers sometimes resort to amazing solutions, which we will discuss in our material.

Judge Harry Pregerson Name Interchange, Los Angeles

One of the most intricate road structures in the world, combining passenger transport routes, the Harbor Transit Road and the Los Angeles Metro Green Line railroad track, was opened in 1993. Located at the junction of I-105 from El Segundo to Norwalk and I-110 from San Pedro to Los Angeles, this tangle of roads bears the name of federal judge Harry Pregerson for a reason. Like a famous lawyer who managed to sort out the wilds of a legal dispute over the construction of I-105, an automobile interchange skillfully resolves endless streams of cars. In just one day, this labyrinth, which allows you to turn in any direction on all sections of the path, crosses more than 500,000 cars. There is only one problem - it is worth missing one, the very right turn, and the miracle of engineering will turn into an endless Möbius strip for you.

Cycle roundabout, Eindhoven

State support for cyclists, deployed in the Netherlands, has led to amazing results: in recent years, most of the country's population prefers to use eco-friendly and economical two-wheeled transport in everyday life. For the convenience of those who preferred to give up cars, special infrastructure began to be created - for example, the unique The Honvering road junction in Eindhoven. Suspended above a busy traffic junction, this circular steel bridge allows traffic to be bypassed. The amazing design is held on the central 70-meter pillar with metal cables, and for reliability, it is also reinforced with concrete columns. The creators of The Hovering say that the future lies precisely in such technologies that nullify traffic accidents and decorate landscapes with unusual futuristic designs.

Gravelly Hill Interchange, Birmingham

The construction of a tangled, like a ball of thread, road junction in Birmingham took four years. Many technological and engineering hurdles stood in the way of the planners who were forced to combine two rail lines and 18 road routes into one network, from the A38 state highway leading from Cornwall to Northampshire, to narrow unnamed country roads, and throw it all over three canals and two rivers. To ensure better traffic and good stability, the builders had to re-lay almost 22 kilometers of road surface and install 59 columns, placing the highway at five different heights. With the light hand of a local newspaper reporter, the result of hard work, which appeared to the world in May 1972, received the playful nickname "Spaghetti Decoupling". Painfully, this frightening design resembles "a mixture of a plate of pasta and an unsuccessful attempt to tie a Staffordshire knot."

Traffic interchange on Taganskaya Square, Moscow

Even those who know the "rules of the game" and have been moving along the Taganka lanes for a long time often get lost on the Garden Ring. What can we say about those who for the first time found themselves at the intersection of the busiest roads in Moscow, spread out in the heart of the Central District of the capital. Where the Bolshoi Krasnokholmsky Bridge connects with Zemlyanoy Val Street, chaos always reigns. Several highways leading from the Lower and Upper Radishevsky, Goncharnaya, Marxistskaya, Vorontsovskaya, Taganskaya, Narodnaya streets and numbering six or more lanes are teeming with endless rows of cars. The incessant noise of passing traffic is cut through by sharp signals, and traffic jams at peak hours do not see any end or edge. A colorful picture of one of the most terrible road junctions in the world is completed by two Moscow metro stations, a bus stop and the almost complete absence of signs.

Interchange at Place Charles de Gaulle, Paris

The ingenious French urban planners who gave Paris the Place des Stars certainly did not have the gift of foresight. Over the past centuries, the “patch” near the famous Arc de Triomphe, lively even by the standards of the 19th century, has turned into a real hell for motorists. Despite the fact that 12 straight and wide avenues diverge from the central city parade ground like the rays of a star, and several metro lines, RER, bus routes and highways converge, there are no traffic lights or priority signs. No wonder that even Parisian taxi drivers, passing through the district a hundred times a day, sigh sadly when they receive an order for Charles de Gaulle Square. Neither intuition, nor a good knowledge of the rules of the road, nor many years of driving experience can save you from the horror that is happening here at rush hour: at the junction, which is ranked among the most difficult roads in the world, several accidents occur per hour.

Road safety is the most important characteristic of a highway. Germany is one of the leading countries in the development of road infrastructure, as well as design standards. According to the basic law, the speed of movement on the autobahns is not limited, with the exception of some sections due to the old surface, repairs or the peculiarities of the road (city). However, statistics claim that in Germany in 2011 4,002 people died on the roads (1 person out of 22,500 inhabitants) [accident statistics in Germany], while in Russia 27,953 people (1 person out of 5,700 inhabitants) [accident statistics in Russia ].

A significant part of accidents can be avoided by choosing the right combination of geometric elements of the road and nodes, warning elements, road equipment elements, etc.

An important condition for road design is that the driver has the right to make mistakes, but the consequences of this mistake should be minimal.

Accordingly, the task of the designer from the point of view of safety is:

Provide comfortable driving conditions that exclude driver error;
In the event of a driver error, minimize its consequences.

Regulation of driver behavior on the road

The geometry of the road and the surrounding situation affect the speed of the vehicle. The wider the carriageway, the higher the selectable single vehicle speed. The straighter the road and the fewer turns, the higher the speed of the vehicle. Moreover, the driver often loses control of distance and speed. He always seems to be moving slowly.

On our roads, very often you can find long straight sections of roads connected by curves of small radius. On the one hand, this geometry allows the driver to develop the maximum speed for the car, on the other hand, the driver has to brake sharply before turning. A road sign warning of a turn may not be noticed by the driver.

Another negative factor of long straight sections is monotony, which leads to loss of attention and drowsiness.

According to the experience of road operation in Germany, it was revealed that, despite the profitability of straight lines in terms of the shortest distance between points, they are also the most dangerous elements of roads for drivers. For example, the most dangerous autobahn in Germany is the A2 Berlin-Hannover, which consists of long straight sections. On the basis of research in Germany, the standard for the maximum length of the straight section L = 20V calculated was adopted. That is, at an estimated speed of 120 km / h, the maximum length of the straight line will be 2400 m.

It is possible to reduce the maximum speed on the site by a variety of combinations of geometry and the surrounding situation. Smooth, consistent curves keep the driver from accelerating. And confined spaces, such as dense buildings or frequent plantings, also convey a sense of danger to the driver, and at high speeds in such conditions, the driver feels uncomfortable.

Compliance of geometric elements with the expectations of the driver

The geometric elements of roads and road junctions must meet the expectations of the driver. Driver expectations are in turn shaped by habits and previous elements. If the previous elements allowed to develop high speed, then it will be very dangerous to arrange a sharp turn after such elements. In order to smoothly reduce the speed of the driver, a sequence of elements with a gradual change in parameters is necessary. For example, it is not safe to insert a radius of 200 meters after a long straight section. However, if you insert several successive curves between the straight and small radius - with a radius of 2000, 1200, 800, 400 meters in decreasing order - then the driver himself will gradually reduce speed and will be safely prepared for a sharp turn.

Consider an example of junction at different levels of the Pipe type. VSN 103-74 states that, depending on local conditions and the traffic situation, a mirror scheme may be applied. The textbook "Intersections and junctions of highways" argues that one of the main determining factors for choosing a junction scheme of the type Pipe is the intensity of left-turn flows.

But in this case, the fact is missed that the driver moving down the left-turn exit to the adjoining road is already prepared for a small radius by the presence of a transitional speed lane, on which, out of habit, the speed decreases. And the driver entering the left-turn exit from the adjoining road, as he was on the main road, remained on it, nothing but signs indicates to him that a small radius is approaching. Based on this argument, in Germany it is recommended to arrange a junction of the Pipe type with ramps on the left side of the overpass, since only in this case it is possible to use the maximum possible radii for this ramp with the highest level of security. In addition, it is necessary to indicate the presence of danger to the driver by the very geometry of the junction. The following figure shows a typical pipe interchange in Germany.

Despite all these conditions, in the latest German standards (2008) it is recommended, if possible, to consider options for a device of a safer type of junction - Triangle.

Conflict points

Conflict points are places of intersection, convergence and divergence of traffic flows. The most dangerous conflict points for transport interchanges are places of parallel crossing of traffic flows. They are related to the rebuilding of two parallel streams. At the same time, their trajectories intersect.

At high intensities, these conflict points not only affect traffic safety, but can also lead to the formation of congestion (see figure below). The driver needs to change lanes and at the same time monitor the situation in the adjacent lane, the intervals to vehicles in both lanes and the speed of vehicles in both lanes, as well as constantly check the blind zone. A particular problem in this case is slowly accelerating heavy-duty road trains, which are simply not allowed to change lanes by nimble cars, and which slow down the entire traffic flow.

It is possible to foresee this situation at the project stage by expert means, knowing the required traffic intensity. In Germany, such an assessment is carried out using a special methodology (to be covered in subsequent articles).

The cheapest improvement might be to lengthen the traffic lane by extending the left turn ramp along the main road. A more expensive solution is to install a direct or semi-direct left turn exit, which will completely avoid the area of \u200b\u200bcrossing flows.

Various form improvements also serve to reduce the number of dangerous zones at interchanges. For example, the most convenient conditions for driving on the main road and in the area of weaving streams are created when the exit on the main road is in front of the entrance. To do this, it is planned to separate the incoming and outgoing flows from the main road by a separate passage.

As a result, instead of two exits and two entrances, there is only one exit on the main course, followed by one entrance. Thus, the intersection area of the flows is transferred from the main road to the exit and the total number of conflict points for the main traffic flow is reduced. The crossing of flows at the congresses occurs at lower speeds. This, in turn, increases the traffic interchange capacity and safety for drivers.

Yesterday I showed you one photo of this interchange, and then all the same I became interested in more detailed information. When it was built, what a name! It's interesting! I share with you, I hope it will be interesting.

The Judge Harry Pregerson Interchange is a stackable interchange near the Athens and Watts neighborhoods in Los Angeles, California. It is located at the intersection of the following highways:

I-105 (Glenn M. Anderson Freeway) - El Segundo, LA Airport, Norwalk
I-110 (Harbor Highway) - San Pedro, Los Angeles

Although the interchange is open to traffic in all directions (unlike the Hollywood Split, East Los Angeles Interchange), it also consists of passenger roads, the Metro Green Line, and the Harbor Transit Road. All this forms a tall, impressive structure, which is the denouement of the name of Judge Harry Pregerson.

It was opened in 1993. The interchange was named after Judge Harry Pregerson. He served as a longtime federal judge and presided over a lawsuit involving the construction of I-105.

This interchange is considered one of the most difficult in the world. It allows you to make a turn in all possible directions on any of the routes. The main thing is not to miss this very turn you need :)

Clickable 1600 px

Vehicles entering a motorway junction from different directions can leave it in all possible directions (full junction). However, the movement of passenger transport is limited on highways. Motorists entering the interchange from east or west via I-105 passenger transit may enter I-110 passenger transit. Motorists entering from the south on the I-110 passenger highway do not have direct access on I-105 and can simply drive further north. Passenger drivers who wish to access a particular highway that does not have a direct link to it must exit the passenger lane at the designated entry/exit point before the interchange and transfer to the main link as is normally done on all passenger lanes in southern California.

The interchange also houses the Harbor Freeway Metro Station, which is both the Los Angeles Metro Green Line and the Harbor Transit Bus Lane that runs down the middle lanes of I-105 and I-110.

An article in the Los Angeles Times called the interchange (later dubbed the Expressway of the Century) "the largest, tallest, most expensive traffic structure ever built by the California Department of Transportation." ". The reporters also noted that "for the first time, the state's transportation engineers combined three transportation models - narrow gauge trains, passenger transport, and cars - into one giant intersection."

Shortly after opening, the fork attracted the attention of many directors. So in 1994 there was a film "Speed" (Speed). In one of the most famous scenes in the movie, the bus had to fly over an unfinished section of the building on an unfinished raised ramp that was still being completed. The fifth level of the overpass (from I-110 southbound to I-105 westbound) that the bus was jumping over had already been completed, so CGI was used in the editing of this scene.

Here is the moment of filming

In 1996, the US Federal Highway Administration awarded Federal Highway 105/110 an "engineering marvel" award for superior road design. By doing so, the government acknowledged that the project had been excellently implemented: traffic jams were reduced, traffic became safer and the air cleaner.

Here are a few more links:

interchange upgrades on I-95 and I-695 near Washington

Here is the process...

Clickable

Automotive denouement, Shanghai, China

The Illinois Department of Transportation (IDOT) hosted a second meeting with the Circle Interchange Project Working Group (PWG)

For me, as a pedestrian, it all looks like this:

I like this way :-)

One of the best highways in Arizona. goes through downtown Phoenix. It is made below ground level, as if in a pit, and due to this there is no noise, dirt, and it does not divide the city into two parts. this is not a federal road - a state highway, but the quality and performance are at the highest level.

sources
http://beway.ru
http://www.skyscrapercity.com
http://grandstroy.blogspot.ru

What you see in front of you in the cover photo is nothing more than a new highway intersection concept that aims to eliminate the need for a left turn, thereby reducing the risk of serious accidents at times. We agree that at first glance, all this heap of lanes looks like complete chaos, but experts say that the future lies behind such safe interchanges.

The concept is actually not new. For the first time, this type of interchange was proposed by an engineering student many years ago, in 2000 this type of interchange appeared on the pages of Gilbert Chlewicki's thesis, although, according to some sources, similar ones were previously built in France, albeit in small quantities.

Since then, interchanges of similar design have begun to appear experimentally on US roads. The experiment was expanded and at the moment there are more than 100 such interchanges in several states.

The largest of these is in Florida, where last year road workers completed a diverging diamond interchange (these huge intersections are so called due to the peculiar form of connection of internal roads) on University Boulevard on the Manatee and Sarasota County line, which at its widest point is up to 12 lanes movement. (A map of "diamond interchanges" around the world can be found here.)

What is the essence and meaning of such a denouement? The concept is pretty simple: fewer stopping points for drivers, more capacity, less congestion, and the complete elimination of left turns that cross oncoming traffic. Here's the official video from the Florida Department of Transportation showing how it all works:

As you can see from the video, crossing two opposite directions of traffic under the bridge removes the need for a left turn against traffic.

True, those of the drivers who have already experienced all the delights of the new generation of automobile urbanization said that in order to understand where to go and how it all works, it is necessary to drive through a difficult intersection several times. It is very rare that someone is able to pass the test the first time and leave in the right direction.

The researchers, however, said that the so-called "diverging diamond decouplings" reduce fatal crashes by more than 60 percent and normal crashes by about 33 percent. They can also be designed with bicycle and pedestrian paths placed on them. This is demonstrated on the video.

How are things at the biggest interchange in Florida? Pretty good, according to a post on the website of America's Transportation Awards, an organization partially sponsored by the AAA and the US Chamber of Commerce.

Since its discovery, motorists using the service have experienced a 40 percent reduction in travel delays, up to 50 percent reduction in car accidents by reducing the number of so-called conflict points, and increased mobility.

What will the new outcomes give and will they appear not only in the USA, but in other countries of the world, for example, in Russia? Mainly, in our opinion, "diamond junctions" show a very important trend of modern major highways. Turning left sooner or later must completely leave them, including in the form of an arrow at a traffic light.