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Esslingen, Germany

Rehborn H.,Daimler AG | Klenov S.L.,Moscow Institute of Physics and Technology | Palmer J.,IT Designers GmbH
IEEE Intelligent Vehicles Symposium, Proceedings | Year: 2011

Based on real traffic data measured on American, UK and German freeways, we study Kerner's common features of traffic congestion phases (synchronized flow and wide moving jam) relevant for many transportation engineering applications. General features of traffic congestion, i.e., features of traffic breakdown and of the further development of congested regions, are shown on freeways in the USA and UK beyond the previously known data examples. For the testing of Kerner's "line J", representing the propagation of the wide moving jam's downstream front, four different methods are studied and compared for each congested traffic situation occurring in the three countries. © 2011 IEEE.

Rehborn H.,Daimler AG | Koller M.,IT Designers GmbH
Journal of Advanced Transportation | Year: 2014

On the basis of real traffic and environmental data measured on German freeways, we studied common features of traffic congestion under the influence of severe weather conditions. We have found that traffic features [J] and [S] defining traffic phases "wide moving jam" (J) and "synchronized flow" (S) in Kerner's three-phase theory are indeed common spatiotemporal traffic features. The quantitative parameters for both traffic phases [S] and [J] were investigated in a comparison of "ideal" weather conditions (good visibility and no precipitation) and severe weather situations (icy road, wind, precipitation, etc.). We showed spatiotemporal congested patterns in several space-time diagrams based on the Automatic Tracking of Moving Jams/Forecasting of Traffic Objects (ASDA/FOTO) model reconstruction for roadside detectors. A statistical study of traffic phase [J] parameters was presented, showing the average values and standard deviation of the quantities. Similarities and differences were analyzed, and some consequences for vehicular applications were discussed to cope with severe weather conditions. © 2013 John Wiley & Sons, Ltd.

Palmer J.,IT Designers GmbH | Rehborn H.,Daimler AG | Kerner B.S.,Daimler AG
Traffic Engineering and Control | Year: 2011

The ASDA and FOTO models developed in the framework of Kerner's three-phase traffic theory exhibit high quality recognition, tracking, and prediction of congested traffic patterns in space and time; for this reason, the ASDA/FOTO models have been used since 2000 in a variety of on-line installations in which traffic data are measured with stationary road detectors. In this article, the ASDA and FOTO models are further developed for the reconstruction, tracking, and prediction of spatiotemporal congested traffic patterns based on probe vehicle data only. The suitability and applicability of these new versions of ASDA and FOTO models is evaluated and proven by using results of microscopic simulations.

Schafer R.-P.,Content Production Unit | Lorkowski S.,Content Production Unit | Witte N.,Content Production Unit | Palmer J.,IT Designers GmbH | And 2 more authors.
Traffic Engineering and Control | Year: 2011

In this article, TomTom's GPS and GSM (Vodafone data) probe vehicle data that are used in TomTom's HD-traffic for vehicle navigation are analysed. We find that the data allows us to reconstruct the structure of traffic patterns with a much greater quality of spatiotemporal resolution than has been possible before. What occurs is that congested traffic in measured traffic patterns consists of two traffic phases of Kerner's three-phase theory, synchronised flow and wide moving jams. We show that TomTom's probe vehicle data opens qualitative new perspectives for the creation of many new ITS applications such as traffic jam warning, input data for traffic control, hybrid vehicle strategies, fuel consumption reduction, etc. TomTom's probe vehicle data processed using the methodology of the three-phase theory provide a basis for the reconstruction of a fine spatiotemporal structure of traffic congestion with a high quality resolution of traffic phases. Additionally, TomTom's probe vehicle data can be efficiently used as an empirical basis of traffic research and engineering.

Pfeiffer D.,Daimler AG | Gehrig S.,Daimler AG | Schneider N.,IT Designers GmbH
Proceedings of the IEEE Computer Society Conference on Computer Vision and Pattern Recognition | Year: 2013

Applications based on stereo vision are becoming increasingly common, ranging from gaming over robotics to driver assistance. While stereo algorithms have been investigated heavily both on the pixel and the application level, far less attention has been dedicated to the use of stereo confidence cues. Mostly, a threshold is applied to the confidence values for further processing, which is essentially a sparsified disparity map. This is straightforward but it does not take full advantage of the available information. In this paper, we make full use of the stereo confidence cues by propagating all confidence values along with the measured disparities in a Bayesian manner. Before using this information, a mapping from confidence values to disparity outlier probability rate is performed based on gathered disparity statistics from labeled video data. We present an extension of the so called Stixel World, a generic 3D intermediate representation that can serve as input for many of the applications mentioned above. This scheme is modified to directly exploit stereo confidence cues in the underlying sensor model during a maximum a posteriori estimation process. The effectiveness of this step is verified in an in-depth evaluation on a large real-world traffic data base of which parts are made publicly available. We show that using stereo confidence cues allows both reducing the number of false object detections by a factor of six while keeping the detection rate at a near constant level. © 2013 IEEE.

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