Classifications

• • G—PHYSICS
  • G08—SIGNALLING
  • G08G—TRAFFIC CONTROL SYSTEMS
  • G08G1/00—Traffic control systems for road vehicles
  • G08G1/09—Arrangements for giving variable traffic instructions
  • G08G1/0962—Arrangements for giving variable traffic instructions having an indicator mounted inside the vehicle, e.g. giving voice messages
  • G08G1/0967—Systems involving transmission of highway information, e.g. weather, speed limits
  • G08G1/096708—Systems involving transmission of highway information, e.g. weather, speed limits where the received information might be used to generate an automatic action on the vehicle control
  • G08G1/096716—Systems involving transmission of highway information, e.g. weather, speed limits where the received information might be used to generate an automatic action on the vehicle control where the received information does not generate an automatic action on the vehicle control
• • G—PHYSICS
  • G08—SIGNALLING
  • G08G—TRAFFIC CONTROL SYSTEMS
  • G08G1/00—Traffic control systems for road vehicles
  • G08G1/01—Detecting movement of traffic to be counted or controlled
  • G08G1/0104—Measuring and analyzing of parameters relative to traffic conditions
• • G—PHYSICS
  • G08—SIGNALLING
  • G08G—TRAFFIC CONTROL SYSTEMS
  • G08G1/00—Traffic control systems for road vehicles
  • G08G1/09—Arrangements for giving variable traffic instructions
  • G08G1/0962—Arrangements for giving variable traffic instructions having an indicator mounted inside the vehicle, e.g. giving voice messages
  • G08G1/0967—Systems involving transmission of highway information, e.g. weather, speed limits
  • G08G1/096733—Systems involving transmission of highway information, e.g. weather, speed limits where a selection of the information might take place
  • G08G1/096758—Systems involving transmission of highway information, e.g. weather, speed limits where a selection of the information might take place where no selection takes place on the transmitted or the received information
• • G—PHYSICS
  • G08—SIGNALLING
  • G08G—TRAFFIC CONTROL SYSTEMS
  • G08G1/00—Traffic control systems for road vehicles
  • G08G1/09—Arrangements for giving variable traffic instructions
  • G08G1/0962—Arrangements for giving variable traffic instructions having an indicator mounted inside the vehicle, e.g. giving voice messages
  • G08G1/0967—Systems involving transmission of highway information, e.g. weather, speed limits
  • G08G1/096766—Systems involving transmission of highway information, e.g. weather, speed limits where the system is characterised by the origin of the information transmission
  • G08G1/096775—Systems involving transmission of highway information, e.g. weather, speed limits where the system is characterised by the origin of the information transmission where the origin of the information is a central station
• • G—PHYSICS
  • G08—SIGNALLING
  • G08G—TRAFFIC CONTROL SYSTEMS
  • G08G1/00—Traffic control systems for road vehicles
  • G08G1/09—Arrangements for giving variable traffic instructions
  • G08G1/0962—Arrangements for giving variable traffic instructions having an indicator mounted inside the vehicle, e.g. giving voice messages
  • G08G1/0967—Systems involving transmission of highway information, e.g. weather, speed limits
  • G08G1/096766—Systems involving transmission of highway information, e.g. weather, speed limits where the system is characterised by the origin of the information transmission
  • G08G1/096791—Systems involving transmission of highway information, e.g. weather, speed limits where the system is characterised by the origin of the information transmission where the origin of the information is another vehicle

Definitions

• the invention relates to a method for recording data about the traffic situation in a road network, wherein a control center of a plurality of vehicles that participate in road traffic and are equipped with a sensor system for recording traffic-relevant sensor data that has at least one the current speed v (t) variable representing the respective vehicle, individual messages about the current traffic situation in the vehicle surroundings recognized by a data processing device arranged in the respective vehicle on the basis of the detected sensor data are transmitted wirelessly.
• the invention further relates to a device in a vehicle for recording and transmitting such individual messages.
• the recording and description of the traffic situation is an essential task in the field of traffic telematics, the aim of which is to provide road users with the most up-to-date and meaningful information possible, so that road users can avoid traffic congestion as far as possible and, if necessary, switch to less congested roads .
• stationary detection devices e.g. beacons, induction loops, etc.
• This is not only associated with very high costs for the creation and maintenance of the required infrastructure, but also has the disadvantage that these facilities only have a locally extremely narrow range of use due to the system. The installation of a huge number of detection devices is therefore necessary for a comprehensive traffic situation detection.
• End users are prepared. For example, the average speed of the respective vehicle could be transmitted to the control center at time intervals. But this is still very expensive. It would be much more effective if a decision could already be made in the vehicle, in which the data acquisition is carried out by means of a suitable sensor system, as to whether the data are more or less important for the traffic situation, and the data transmission may only be important Data is limited. In this regard, it would be of great interest if, for example, one could restrict oneself to the transmission of only information about a traffic jam.
• a traffic situation detection system based on "floating cars", in which large amounts of messages about events which are unusual and therefore significant from the point of view of the individual "floating cars" are automatically generated, these messages must first be subjected to a thorough check before they occur in traffic services, such as route planning, route guidance of vehicles, traffic planning or traffic forecasts.
• traffic services such as route planning, route guidance of vehicles, traffic planning or traffic forecasts.
• the sensors in the "floating cars” are kept as simple as possible for cost reasons, there will inevitably be a confusion between different types of events when the sensor data is automatically evaluated.
• a particularly drastic example is the confusion of the "traffic jam” event with the "stop at a rest stop” event during a motorway trip. In both cases, the vehicle speed is detected by the sensors.
• the object of the invention is therefore to develop a generic method in such a way that an at least largely automatable control of
• Event reports can take place in the headquarters with sufficient reliability. Furthermore, a device in a vehicle is to be proposed which can be used for the acquisition and transmission of traffic situation data within the scope of a method according to the invention.
• the invention solves this problem for a generic method in that the individual messages transmitted from the "floating cars" to the central office are put together in a certain way.
• they not only include a classifying interpretation of the existing traffic situation in the vehicle environment, which is carried out by the data processing device carried in the vehicle on the basis of the recorded speed variables, but also includes a confidence factor F, which is determined by the data processing device from the recorded speed variables is formed.
• This confidence factor F is formed in such a way that it represents a measure of the ripple in the time profile of the recorded speed variables for the period to which the individual message relates.
• These speed variables are preferably the current speeds v (t) of the vehicle. Of course, it is also easily possible to use other sizes with appropriate information.
• the ripple of the profile of the speed variables means a comparison variable which represents a statement about the "intensity" of the temporal fluctuations of the respective speed variable.
• the confidence factor F is preferably formed in that calculates the approximate length of the graph v (t), ie the current speed of the respective "floating car", over the period of time to which the individual message relates and then the length of this graph v (t) with the aid of a predetermined reference speed and the measurement frequency f used in the determination of the sensor data (ie the determination of the speed variables) is standardized.
• any speed value can be used as the reference speed.
• Vm the minimum vehicle speed
• Vm the minimum vehicle speed
• the data processing device in the respective "floating car” only assumes traffic-related congestion when the sensor system determines a vehicle speed v (t) that is less than or equal to the predefined threshold value v mln .
• this reference speed is changed by the control center if necessary and transmitted to the individual "floating cars" by wireless means.
• the sensitivity of the method can be specifically changed in this way. This can be useful, for example, in order to meet the requirements of a national highway with usually higher speeds in contrast to a city highway in a metropolitan area with correspondingly lower speeds.
• the formation of the confidence factor F according to the following relationship has proven particularly useful in practical experiments:
• N the thickness of this index set and t the times at which speed measurements were carried out.
• the invention is based on a device that a Sensor system for recording data, which includes data (speed variables) representative of at least the current vehicle speed, and has a data processing device which is connected to this sensor system. Furthermore, this device comprises a communication device for the wireless transmission of individual messages, which are characteristic of the current traffic situation in the vehicle environment, to a control center.
• the programming of the data processing device is set up in the following way: on the basis of the detected speed variables, the data processing device carries out a classifying interpretation of the traffic situation in the vehicle surroundings, this interpretation at least comprising the class "traffic-related disruption" (traffic jam).
• the data processing device uses the detected speed variables to form a confidence factor F, which represents a measure of the ripple in the temporal profile of the speed variables for the period to which the individual message relates, in particular for the time interval for driving through a traffic jam.
• the data processing device compiles the individual messages to be transmitted to the control center via the communication device in such a way that they each include at least the classifying interpretation of the traffic situation in the vehicle environment and the confidence factor F.
• Fig. 1 scheme of a traffic situation detection system
• Fig. 2 frequency distributions for true and false traffic jams in
• the diagram of a traffic situation detection system shown in FIG. 1 is subdivided into function blocks which belong to a center for recording the traffic situation data and into function blocks which are each assigned to the individual “floating cars”.
• the starting point is the acquisition of sensor data by an appropriate sensor system in the respective "floating car”.
• the data processing device of the "floating car" connected to the sensor system determines a confidence factor F from these sensor data, which preferably consists of the current speed of the respective vehicle, preferably according to the formula described above.
• the values required for the reference speed v ⁇ ,, and possibly the length of the measuring interval and the measuring frequency f may vary from the
• Data processing device of the "floating car” can be taken from a memory which is referred to in FIG. 1 as "default configuration". Via a transmitter / receiver (communication) for wireless data exchange with the control center, the default settings can be changed if necessary.
• the data processing device of the "floating car” makes a classifying interpretation of the traffic situation in the vehicle surroundings on the basis of the speed variables detected by the sensors and determines the confidence factor F for this purpose.
• the interpretation of the traffic situation, in particular the class "traffic-related disruption" Traffic jam messages are transmitted to the head office as individual messages together with the confidence factor determined via the "Communication" function block.
• the transmitter / receiver of the control center which is also symbolized by a “Communication” function block, records the individual messages transmitted and saves them.
• a data record for a change in the preset values in the "floating cars" can be taken from the function block of the central station designated with "preset configuration".
• the data processing device (not shown in more detail in the head office) checks each individual message received based on the associated confidence factor that is transmitted in each case, whether the interpretation of the traffic situation made by the "floating car” was probably correct or whether it appears doubtful.
• the vehicle speed zero can occur not only in the case of a traffic jam caused by high traffic volume, but also in the case of a scheduled stop at a rest stop or in a parking lot of a motorway.
• a traffic jam caused by a high volume of vehicles usually announces itself through characteristic fluctuations of the speed professional.
• a scheduled stop in a parking lot or at a rest area usually has a relatively smooth speed profile immediately before this stop. But it can also happen that a sudden traffic jam caused by someone
• the present invention enables high reliability of the informative value of traffic information.
• a largely automatic evaluation of the recorded individual information takes place.
• Manual evaluation only has to be carried out for a considerably smaller part of the individual reports recorded in order to ensure reliable input data for the traffic information to be derived. This ensures the cost-effectiveness of high-quality data acquisition.
• Fig. 2 the effectiveness of the method according to the invention is schematic, i.e. not shown to scale using frequency distributions.
• the frequency distributions p (F) were plotted as a function of the confidence factor F for a large number of single reports, the confidence factor of which was determined in each case according to the calculation formula given above, whereby those individual reports for which the automatic evaluation of "traffic-related traffic jam" actually were evaluated as curve a was true.
• curve b shows the frequency distribution for those individual messages which were incorrectly interpreted as traffic jam by the automatic evaluation in the "floating cars". It can be seen from the illustration that individual traffic jams with a confidence factor of about 0.4 or greater have an extraordinarily high level of reliability, since only very few individual messages with a higher confidence factor F are incorrectly classified in this category.

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• 1997
  • 1997-01-29 WO PCT/DE1997/000229 patent/WO1997029471A1/fr active IP Right Grant
  • 1997-01-29 JP JP9528050A patent/JP2000504860A/ja active Pending
  • 1997-01-29 AT AT97914127T patent/ATE188059T1/de not_active IP Right Cessation
  • 1997-01-29 DE DE59700887T patent/DE59700887D1/de not_active Expired - Lifetime
  • 1997-01-29 US US09/117,941 patent/US6092020A/en not_active Expired - Lifetime
  • 1997-01-29 EP EP97914127A patent/EP0879460B1/fr not_active Expired - Lifetime

Non-Patent Citations (1)

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