Traffic congestion
The term traffic jam (short jam) denotes a strong faltering or stalled traffic flow on a road. As one of the reasons for this is considered too high a number of vehicles per unit time ( or per length). The causes of a traffic jam are so alone, however, can not be explained. Contrary to hold one of the traffic jam for Moving traffic.
Congestion - even those on waterways, railroad tracks, airports or in space ( " hold " ) - are a subject of research in transportation science.
Transportation experts distinguish between "Jam " and " congested traffic ." In Switzerland, for example, is " technically " speaking of a traffic jam, when the traffic flows at least for a minute with less than 10 km / hr. If the velocity in the range between 10 and 30 km / hr, one speaks of congested traffic.
- 3.1 traffic jam warning system
- 3.2 Radio
- 3.3 Further information channels
Causes
Typically, the capacity of a road is 1500 to 2500 vehicles per hour per lane. On sale can be the capacity, for example by unfavorable weather such as rain, snow or ice and ineffective behavior of road users, for example by curiosity. This can cause jams out of nowhere, where hidden from the road users even after the end of the jam, the cause remains (as opposed to an accident in which you can see the scene of the accident when passing as a cause ).
A locally reduced capacity of the traffic by events such as lane closures due to road works or accidents and lane constrictions for example, before tunneling the traffic jam formation favoring further. Such kapazitätslimitierende narrowing of the traffic route is also called bottleneck.
However, an increased volume of traffic may be responsible for congestion. Reasons for this may be rush hour travel ( especially at the beginning and at the end of vacation and samstäglicher " bed change" in tourist areas ) and major events.
Congestion detection
Visual observation
About voluntary jam detector, police patrols, cameras and helicopters roads and transport hubs be visually observed.
Stationary detection system
By means of permanently installed sensors on the highway the traffic flow is measured objectively. Here, only the left lane is monitored because of the parameters distance and speed in the left lane to the traffic density of the other tracks can be closed. On German highways located on average every 4 km, a sensor, so here are a total of 4000 sensors in use.
Floating Car Data (FCD ) / Floating Phone Data (FPD )
In this modern method in vehicles carried (mobile phones ) or built-in appliances (usually with a transmitter equipped GPS receiver ) to measure the traffic speed and travel time are used. The method Floating Cellular Data with the mobile phones is less precise than GPS, but much cheaper, since no additional hardware (mobile phones ), infrastructure ( antennas) or network load ( sending data ) is necessary and sufficient for accurate general statements.
The network operator anonymize the signals of the mobile phones and analyze them by specialist firms on speed. These data are useful and basis for most of Intelligent Traffic Systems (ITS ) such as active traffic management, emergency and Evakuationsmanagement, congestion avoidance, time estimation. It offers a real-time picture of the current traffic situation; advanced software is based on the real-time data and traffic pollution and congestion predict ( predictive ).
FCD method using mobile phones have over conventional systems (sensors, cameras, etc.) with great benefits:
- Low-cost, since no additional equipment or networks are required
- Not only highways but also roads are recorded
- No installations on the route.
There are regarding the use of data privacy concerns.
Jam message
Traffic jam warning system
Warning of road users with the help of danger signs (Z 124 ), or by the display of texts. In addition, speed limits can be arranged. Congestion warning systems have mostly an automatic detection and come gantries in the form of variable message signs are used.
Radio
Traffic reports are read in traffic and sent via TMC ( Traffic Message Channel) in the non- audible range of the FM signal in digital form. However, the TMC area is very narrow, so that all messages are transmitted only about every fifteen minutes. Moreover, since it often happens that a receiver missed a message, the reception of the TMC message may be considerably delayed. Traffic reports on TMC can be received and processed by navigation systems.
More info channels
Traffic reports are published in the teletext and the Internet from different providers. Furthermore, they can be queried individually via mobile phones. For this purpose, the location of the inquirer is automatically located and queried more information route.
Behavior in traffic
Because a traffic jam beside delays also carries the risk of accidents, there is the ADAC and other stakeholders Notes on Performance:
- On the highway, turn on the hazard lights and watch the traffic.
- Slide brake to avoid a collision of the following vehicle.
- At the " tailgating " on the jam Keep a safe distance.
- Stop In predictable longer waits engine.
- Not slow When approaching and passing a safe accident sites.
On highways, a rescue alley is in a traffic jam release in the middle of two lanes, with three - or multi-lane roads between the two left lanes. Blocks a vehicle, the emergency lane, has about 4 feet in front of and behind the obstacle in the right lane, a gap be left.
In still flowing traffic any column jumping should be omitted. The emergency lane may only be used on police statement as lanes ( to get around to the next motorway exit). In exceptional cases (eg A99 Munich ring ) can be released by appropriate signs of the hard shoulder to traffic.
Follow
For directly affected jam participants quantifiable effects may be due to the loss of time. Economically if we include congestion losses in the billions high. Working hours, traffic-related accident costs, fuel consumption can be estimated so. In Germany such estimates reach up to 100 billion euros. On average, according to these estimates, spends every citizen fifty hours per year in traffic jams.
Psychological approaches in the congestion Research
Common explanations of traffic university professors such as Michael Schreckenberg, physicist, University of Duisburg -Essen, or Martin Driver, Physics, Technical University of Dresden proceed from physical operating parameters whose interpretation is tantamount to highlight the "wrong " driving behavior and high driving speed and congestion cause.
In contrast, no longer controversial for decades that driver behavior is essentially based on the perception of roadway and peripherals. Behavior -determining contents of perception in the field of vision, for example, depth and width of the field of view. To view field truncations lead to spontaneous slowdown, while, conversely, increase the field of view leads to acceleration. Speed -changing parameters are luminance and color contrasts, density and abrupt changes in the visual field. These parameters are not only detected in road layout and periphery, but are also expected by the occurrence of the same direction vehicles in the field of view.
The driver required on the part of physics ability to meet a defined distance to the vehicle ahead, go for that reason alone into the void, because the perception and reaction apparatus of man does not provide for such a mileage. From the flow physics derived transport models sick throughout mind that people operate differently than a physical flow unit.
Superlatives
The Guinness Book of World Records lists the longest traffic jam in the world in 1980 between Paris and Lyon 176 km in length. If one also considers congestion in a contiguous route network and not only on a single route, it has now been surpassed. On 11 June 2009, there were around 19 in São Paulo local time clock in the route network of the metropolitan area of storage on a total of 293 km in length.
A traffic jam in Russia on December 2, 2012 had officially stated but according to media reports a length of 200 km, with 20 km.
Literary processing
- Daniel Kampa (ed.): Not again jam! Sneaky travel stories, an anthology of John Irving, Doris Dorrie, Martin Suter, Anna Gavalda among other things, Diogenes, Zurich 2009, ISBN 978-3-257-23949-2 ( as an audio book: Speaker: Tommi Piper, Anna King, 75 minutes, CD, ISBN 978-3-257-80267-2 ).