United States Department of Transportation
i
Network origin-destination demand estimation using limited link traffic counts : strategic deployment of vehicle detectors through an integrated corridor management framework.
-
2009-10-15
-
[PDF-1.11 MB]
Details:
-
Creators:
-
Corporate Creators:
-
Corporate Contributors:
-
Subject/TRT Terms:
-
Publication/ Report Number:
-
Resource Type:
-
Geographical Coverage:
-
Corporate Publisher:
-
Abstract:In typical road traffic corridors, freeway systems are generally well-equipped with traffic surveillance systems such as vehicle detector (VD) and/or closed circuit television (CCTV) systems in order to gather timely traffic information for traffic control and/or management purposes. However, other highway facilities in the corridor, especially arterials and surface streets in the vicinity of the freeway, mostly lack detector/sensor systems. Yet, most traffic management and control methods/frameworks in the literature assume the availability of time-dependent traffic measures (such as counts, flows, speeds, etc.) on all links of the corridor. Hence, there is a critical disconnect between the practical reality and methodological expectations in terms of detection capabilities. This research seeks to develop a mechanism to strategically deploy vehicle detectors to infer network origin-destination (O-D) demands using limited link traffic count data. It leads to the problem of the identification of “optimal” locations for installing detectors so that maximum system observability is achieved with a limited monetary budget. From an integration standpoint, it addresses the question of where to locate detectors on the non-freeway facilities so that, in conjunction with the installed detectors on freeways, the entire corridor can be managed effectively by obtaining the maximum possible accurate information on traffic conditions.
The primary goal of the first stage of this project is to address the network sensor location problem (NSLP) directly so as to obtain the unobserved link flows given the minimum subset of observed link flows provided by passive counting sensors. It circumvents the data needs (in terms of turning movement proportions or prior O-D structure) or assumptions (on traffic assignment rules) associated with the O-D demand estimation problem where the NSLP is a sub-problem. A simple and efficient linear algebra based method is proposed to solve the NSLP. Given the link-path incidence matrix to represent the network topology, the concept of linear independence in relation to a set of links is used to identify the minimum subset of network links to equip with vehicle sensors so as to estimate the flows on all links. This subset of links constitutes the “basis” of the vector space of the link-path incidence matrix, and the proposed approach is labeled the basis link method. The approach does not require any assumption on road users’ route choice behavioral rules and/or traffic assignment principles. Also, by solving the NSLP independently rather than as a sub-problem of a specific application, it allows applicability to many link-based applications in transportation planning and traffic management, such as pavement management systems, congestion pricing, and link strengthening for disaster response. It can also serve as a platform to address broader problems such as network O-D estimation or link travel time estimation.
-
Format:
-
Collection(s):
-
Main Document Checksum:
-
Download URL:
-
File Type:
