Traffic jam
A traffic jam ( traffic jam for short ) or a traffic blackout is a very slow or stalled traffic flow on a street . One of the reasons for this is too high a number of vehicles per time unit (or per route length). However, traffic jams can also arise even though the capacity of the road was sufficient with evenly distributed and flowing traffic. In contrast to stopping, the traffic jam counts as flowing traffic .
Traffic jams - including those on waterways , railroad tracks , at airports or in the air (“ waiting loop ”) - are a subject of research in transport science . Escape routes for pedestrians in buildings and at major events are designed to be wide and fluid to reduce the risk of congestion and the number of visitors is limited.
Traffic experts differentiate between "traffic jams" and "slow traffic". The ADAC speaks of a traffic jam if several vehicles are fast for at least five minutes on average below 20 km / h and that over a length of at least one kilometer. At the same time, slow traffic between 20 and 40 km / h is assumed. In Switzerland, for example, the term “traffic jam” is used when road traffic flows for at least one minute at less than 10 km / h. If the speed is in the range between 10 and 30 km / h, one speaks of slow traffic.
causes
Typically, the capacity of a road is 1500 to 2500 vehicles per hour and lane. The capacity can be reduced, for example, by unfavorable weather conditions such as rain, snow or black ice, as well as ineffective behavior by road users , for example through curiosity . As a result, traffic jams can arise out of nowhere , in which the cause remains hidden to road users even after the end of the traffic jam (in contrast to accidents and construction sites, where the causes can be identified when driving past).
A locally reduced capacity of the traffic route due to events such as lane closures due to construction sites or accidents as well as lane narrowing, for example in front of tunnels, also favor the formation of traffic jams. Such a capacity-limiting narrowing of the traffic route is also called a bottleneck .
An increased volume of traffic can also be responsible for traffic jams. Reasons for this can be rush hour traffic , tourist traffic (especially at the beginning and at the end of holidays as well as Saturday “ bed changes ” in holiday areas) and major events .
Traffic jam detection
- Visual observation
Roads and traffic junctions are visually observed via voluntary traffic jam detectors, police patrols, cameras and helicopters.
- Stationary registration system
The traffic flow is measured objectively by means of permanently installed sensors on the motorway . Only the left lane is monitored here, as the traffic density of the other lanes can be inferred from the parameters distance and speed in the left lane. On German autobahns there is an average sensor every 4 kilometers, so that a total of around 4,000 sensors are in use here.
- Floating Car Data (FCD) / Floating Phone Data (FPD)
With this modern method, mobile phones or devices installed in vehicles ( usually GPS receivers equipped with a transmitter ) are used to measure the speed of traffic and travel time. The floating cellular data procedure with mobile phones is less precise than GPS, but much cheaper, as no additional hardware (mobile phones), infrastructure (antennas) or network load (sending data) is necessary and it is sufficiently precise for general statements.
The network operators anonymize the signals from the mobile phones and have them analyzed for speed by specialist companies. This data is useful and the basis for most Intelligent Transportation Systems (ITS) , such as active traffic management, emergency and evacuation management, traffic jam avoidance, time estimation. It offers a real-time picture of the current traffic situation; Advanced software will also predict traffic load and congestion based on real-time data.
FCD processes using cell phones have great advantages over conventional systems (sensors, cameras, etc.):
- Cheaper because no additional equipment or networks are required
- Not only highways, but also secondary roads are recorded
- No installations on the route.
There are data protection concerns regarding the use of this data.
Traffic jam report
Traffic jam warning system
Road users can be warned with the help of appropriate hazard signs or by displaying texts. In addition, speed limits can be imposed or alternative routes suggested. In the Gotthard traffic jam, for example, the San Bernardino route is suggested. Traffic jam warning systems usually have automatic detection and are used on gantries in the form of variable message signs .
radio
Traffic reports are in traffic read and TMC ( Traffic Message Channel sent) in the inaudible range of the FM signal in digital form. However, the TMC range is very narrow, so that all messages are only transmitted approximately every 15 minutes. In addition, since a recipient often misses a message, the reception of the TMC message can be significantly delayed. Traffic jam reports via TMC can be received and processed by navigation systems .
Further information channels
Traffic jam reports are published by various providers in teletext and on the Internet. They can also be queried individually via mobile phones . For this purpose, the position of the inquirer is automatically localized and further information on the route is requested.
Behavior in traffic jams
Since a traffic jam not only entails delays but also the risk of accidents, the ADAC , ASTRA or other interest groups provide information on driving behavior, which are usually as follows:
- Switch on the hazard warning lights on the motorway and watch the traffic.
- Brake smoothly to avoid colliding with the following vehicle.
- Keep a safe distance when "driving" into the traffic jam.
- If longer waiting times are foreseeable, switch off the engine, immediately in tunnels.
- Do not brake when approaching or passing secured accident sites.
- Switch on traffic radio or TMC and wait for information about the duration of the traffic jam (e.g. lane closure ).
On motorways in traffic jams in Germany, Austria, the Czech Republic and Hungary, an emergency lane must be left free in the middle of the two lanes; with three- or multi-lane lanes, there are different national regulations between which lanes the emergency lane must be formed. All entrances must be left free, regardless of whether they are a makeshift connection point or a normal connection point, so that post-alarm workers can turn into the rescue alley. In Switzerland and Slovenia, the formation of an emergency corridor is expressly recommended.
When the traffic is still moving, you should refrain from jumping into the column . The hard shoulder may only be used as a lane if instructed by the police (e.g. to get to the next motorway exit). In exceptional cases (e.g. A99 Ring München or A1 Morges – Ecublens), the hard shoulder or hard shoulder can be opened to traffic by means of appropriate signs.
Wrong driver in the rescue alley
Driving after emergency vehicles in the rescue alley is prohibited
Overtaking is also prohibited for motorcycles in traffic
Changing lanes in a traffic jam
consequences
For those directly affected, the loss of time can cause quantifiable damage. In economic terms, traffic jam damage is extrapolated into billions. Working hours, traffic jam-related accident costs and fuel consumption are also estimated. In Germany, such estimates reach up to 100 billion euros. According to these estimates, every German citizen spends an average of 50 hours per year in traffic jams.
Avoidance
There are several ways to avoid traffic jams. In the context of a traffic turnaround, traffic avoidance is a means of avoiding traffic jams. Classic approaches in transport policy rely on the expansion of the roads. B. also the conversion of intersections to roundabouts . However, roundabouts cannot completely or always avoid traffic jams, since roundabouts, if they are highly frequented, can result in other, nearby (!) Traffic routes and traffic light-free intersections there with traffic jams or considerable impairments. Promoting other modes of transport also helps avoid traffic jams.
Psychological approaches in traffic jam research
Common explanations of traffic university professors, such as the physicist Michael Schreckenberg and Martin driver to go from physical operating parameters from which interpretation is tantamount to "false" ride and high travel speed are jam cause.
In contrast, it has not been disputed for decades that driver behavior is essentially based on the perception of the road and the periphery. Perceptual content that determines behavior in the driver's field of vision is, for example, the depth and breadth of the field of vision. Shortening the field of view leads to a spontaneous slowdown, while conversely, an expansion of the field of view leads to acceleration. Speed-changing parameters are also brightness and color contrasts, density and abrupt changes in the field of vision. These parameters are not only proven in the road layout and periphery, but are also expected when vehicles in the same direction enter the field of vision.
The ability of the driver to maintain a defined distance from the vehicle in front, which is required by physics, is ineffective because the human perception and reaction apparatus does not provide for such driving performance. Traffic models derived from flow physics suffer from the fact that people move differently than a physical flow unit.
Superlatives, statistics
The Guinness Book of Records lists the longest traffic jam in the world in 1980 between Paris and Lyon with a length of 176 km. If you also consider traffic jams in a coherent route network and not just on a single route, this has now been exceeded. On June 11, 2009, around 7 p.m. local time in São Paulo , there was a traffic jam in the metropolitan area network for a total of 293 km.
According to media reports, a traffic jam due to the onset of winter on December 2, 2012 on the M10 motorway north of Moscow was 200 km long; but officially it was given as 20 km.
TomTom publishes an annual traffic index with statistical information on over 400 cities, which the company compiles from data from its navigation devices. It named Hamburg, Berlin, Wiesbaden, Munich, Nuremberg, Stuttgart, Bonn, Kassel, Bremen and Frankfurt am Main as the most congested German cities (measured by how many percent longer a trip takes due to a traffic jam).
See also
Literary processing
- Daniel Kampa (Ed.): Not another traffic jam! Sneaky travel stories, an anthology with John Irving , Doris Dörrie , Martin Suter , Anna Gavalda and others. a., Diogenes, Zurich 2009, ISBN 978-3-257-23949-2 (as audio book: speakers: Tommi Piper , Anna König , 75 minutes, CD , ISBN 978-3-257-80267-2 ).
Web links
Individual evidence
- ↑ When does a traffic jam become a traffic jam? In: t-online.de. Retrieved May 2, 2020 .
- ↑ Definitions. In: astra.admin.ch. Federal Roads Office, accessed on September 9, 2018 .
- ↑ Institute f. Transport (Ed.): From the beginnings to the present Transport technology at the University of Kassel , Kassel University Press, 2005, ISBN 3-89958-303-5 , page 15
- ↑ Federal Roads Office FEDRO: Behavior in traffic jams. Retrieved May 4, 2017 .
- ↑ Daniele Mariani: Warning traffic jams - The watchdogs over the traffic. In: swissinfo.ch . April 17, 2014, accessed June 5, 2020.
- ↑ The roundabout is the better intersection. In: sueddeutsche.de . December 9, 2014, accessed June 9, 2020.
- ↑ The new leaflet for the construction of roundabouts. New guidelines for road design. University of Karlsruhe (TH), December 12, 2006
- ↑ see already Leutzbach & Papavasiliou, 1988! and Brackstone, 2000.
- ↑ Brazil: The longest traffic jam in the world was 293 kilometers long. In: mz-web.de. June 11, 2009, accessed December 7, 2018 .
- ↑ Russian drivers trapped in giant traffic jam. In: bbc.com. December 2, 2012, accessed October 20, 2018 .
- ↑ www.tomtom.com: Traffic Index 2019
- ↑ Hamburg is Germany's traffic jam capital. In: spiegel.de . January 29, 2020, accessed May 4, 2020.