Examining the potential of floating car data for dynamic traffic management

Traditional traffic monitoring systems are mostly based on road side equipment (RSE) measuring traffic conditions throughout the day. With more and more GPS-enabled connected devices, floating car data (FCD) has become an interesting source of traffic information, requiring only a fraction of the RSE infrastructure investment. While FCD is commonly used to derive historic travel times on individual roads and to evaluate other traffic data and algorithms, it could also be used in traffic management systems directly. However, as live systems only capture a small percentage of all traffic, its use in live operating systems needs to be examined. Here, the authors investigate the potential of FCD to be used as input data for live automated traffic management systems. The FCD in this study is collected by a live country-wide FCD system in the Netherlands covering 6-8% of all vehicles. The (anonymised) data is first compared to available road side measurements to show the current quality of FCD. It is then used in a dynamic speed management system and compared to the installed system on the studied highway. Results indicate the FCD set-up can approximate the installed system, showing the feasibility of a live system

Multi-scale analysis of linear data in a two-dimensional space

Many disciplines are faced with the problem of handling time-series data. This study introduces an innovative visual representation for time series, namely the continuous triangular model. In the continuous triangular model, all subintervals of a time series can be represented in a two-dimensional continuous field, where every point represents a subinterval of the time series, and the value at the point is derived through a certain function (e. g. average or summation) of the time series within the subinterval. The continuous triangular model thus provides an explicit overview of time series at all different scales. In addition to time series, the continuous triangular model can be applied to a broader sense of linear data, such as traffic along a road. This study shows how the continuous triangular model can facilitate the visual analysis of different types of linear data. We also show how the coordinate interval space in the continuous triangular model can support the analysis of multiple time series through spatial analysis methods, including map algebra and cartographic modelling. Real-world datasets and scenarios are employed to demonstrate the usefulness of this approach

Advanced OR and AI Methods in Transportation THE LINK TRANSMISSION MODEL: AN EFFICIENT IMPLEMENTATION OF THE KINEMATIC WAVE THEORY IN TRAFFIC NETWORKS

Abstract. This paper describes a numerical solution method for a dynamic network loading model that is consistent with the first order kinematic wave theory. The proposed procedure, called link transmission model (LTM), only requires calculations at network nodes. Compared to the cell transmission model (CTM), the computational complexity of the LTM is about n times smaller for the same level of accuracy, where n is the mean amount of cells in a homogeneous network link. 1

Effect of clinical examination and anatomical location on native arteriovenous fistula maturation rate in high risk patients

BACKGROUND: Maximal use of native arteriovenous fistulas (AVFs) for patients on hemodialysis therapy remains a clinical challenge. Primary failure rates remain high with risk factors such as female gender, diabetes mellitus, lower arm AVF and higher age. We wondered if a strategy of careful clinical examination prior to AVF creation and a preference towards an upper arm AVF in case of doubt about the quality of the vein in patients with any of the above mentioned risk factors, would lead to better maturation rates. METHODS: The records of all patients who received an AVF between January 2005 and December 2009 at our University Hospitals Leuven were studied retrospectively. Demographic data, comorbidity, fistula characteristics, fistula maturation and fistula complications were recorded and analyzed. RESULTS: Of 344 patients enrolled, 156 (45.3%) received a lower arm AVF and 188 (54.7%) an upper arm AVF. Two hundred and seventy-six (80.2%) fistulas had a normal maturation. Lower arm AVF was a significant risk factor for non-maturation in this series (73.1% versus 86.2% ; p = 0,0024). Female gender, diabetes and high age were not, but female gender showed a significant difference in distribution in upper arm versus lower arm fistulas (62.40% versus 37.6% ; p = 0,0218). CONCLUSIONS: Careful clinical examination prior to upper or lower arm AVF creation together with the integration of risk assessment in the planning of AVF is worthwhile. A preference towards upper arm fistulas if major risk factors are -present can improve overall maturation rates and lead to the same maturation rates as in the overall dialysis population. Therefore, the presence of risk factors for non-maturation should not lead to the underuse of native AVFs.status: publishe

Reconstructing mesoscopic traffic state, vehicle trajectories, and lane change behavior by fusing individual sensor and high-resolution floating car data

status: publishe

Automated incident detection using real-time floating car data

The aim of this paper is to demonstrate the feasibility of a live Automated Incident Detection (AID) system using only Floating Car Data (FCD) in one of the first large-scale FCD AID field trials. AID systems detect traffic events and alert upcoming drivers to improve traffic safety without human monitoring. These automated systems traditionally rely on traffic monitoring sensors embedded in the road. FCD allows for finer spatial granularity of traffic monitoring. However, low penetration rates of FCD probe vehicles and the data latency have historically hindered FCD AID deployment. We use a live country-wide FCD system monitoring an estimated 5.93% of all vehicles. An FCD AID system is presented and compared to the installed AID system (using loop sensor data) on 2 different highways in Netherlands. Our results show the FCDAID can adequately monitor changing traffic conditions and follow the AID benchmark. The presented FCD AID is integrated with the road operator systems as part of an innovation project, making this, to the best of our knowledge, the first full chain technical feasibility trial of an FCD-only AID system. Additionally, FCD allows for AID on roads without installed sensors, allowing road safety improvements at low cost