Cross-cutting Issues

A triple left-turn lane system was constructed at the interchange of US Highway 59 (US 59) at State Highway 6 (SH 6) in the City of Sugar Land, Texas in November 2009.  The system consists of an overhead dynamic message sign and in-pavement lights on the US 59 southbound frontage road approach to the interchange. The dynamic message sign displays two left-turn arrows and a shared left-through arrow alternating with “STAY IN YOUR LANE” message at approximately 800 feet from the intersection.  The in-pavement lights delineate the three left-turn lanes through the intersection with two sets of lights following the pavement markings.  This project was needed due to the high traffic demand of the south-to-east movement from Houston to Sugar Land and Missouri City.  This diamond interchange has six and seven-lane approaches on the US 59 frontage roads and five-lane approaches on SH 6.

City of Sugar Land, Texas

Brown & Gay Engineers, Inc.

Presented at the ITS America Annual Conference and Exposition, May 3-5, 2010, Houston, Texas

Urban expressways play an important role in urban road networks. Although automatic incident
detection (AID) methods have been studied for a long time, most of the existing AID algorithms are designed for freeways and not explicitly consider the detection of incidents near ramps under frequent in and out flows. However, urban express ways usually have short spaced on ramps and off ramps, which makes the traffic flow characterizes quite different from the ones of freeways.  In addition, expressways usually have heavy traffic flow, which makes it more difficult to distinguish incidents from congestions.  This paper presents an automatic incident detection (AID) method for urban expressways, using loop detector data. An expressway is divided into short segments based on detector locations and the geometric conditions. The volume and occupancy data from the loop detectors are used to determine the upstream and downstream density difference for a specific segment. The incident warming is triggered by the significant change of the density difference. An experiment was conducted to investigate the performance of this method, using actual incident data from Shanghai, China. The results indicate that this method has good performance and is suitable for urban expressways.

Authors: Miao Zhang, Ph. D., Yang Cheng, Ph. D., Dongyuan Yang, Ph. D.

Presented at the 18th World Congress on ITS, October 2011, Orlando, Florida

The aim of this paper is to explore a new approach to obtain better traffic demand (Origin-
Destination, OD matrices) for dense urban networks. From reviewing existing methods, from
static  to  dynamic OD matrix  evaluation,  possible  deficiencies in the approach  could be
identified:  traffic assignment details for  complex  urban network and lacks in dynamic
approach. To improve the global process of traffic demand estimation, this paper is focussing
on a new methodology to determine dynamic OD matrices  for urban areas characterized by
complex route choice situation  and  high level of traffic controls. An iterative bi-level
approach will be used,  the Lower level  (traffic assignment)  problem will determine,
dynamically,  the utilisation of the network by vehicles using heuristic data from mesoscopic
traffic simulator  and the Upper level  (matrix adjustment)  problem will  proceed  to an OD
estimation  using  optimization Kalman filtering technique.  In  this way, a full dynamic and
continuous estimation of the final OD matrix could be obtained. First results of the proposed
approach and remarks are presented.

Traffic Facilities  Laboratory (LAVOC)
Ecole Polytechnique Fédérale de Lausanne (EPFL)
Switzerland

Presented at the ITS America Annual Conference and Exposition, November 16-20, 2008, New York, New York

It is a challenge to measure and predict average travel speeds on signalized urban arterials, because urban street often includes multiple signalized intersections, which causes control delay consisting of initial deceleration delay, queue move-up time, stopped delay, and final acceleration delay. This study describes the process being taken by the New York City Department of Transportation to design, test and implement a performance measurement system along Lower Manhattan arterials.

New York City DOT

TransCore ITS, LLC

Presented at the 18th World Congress on ITS, October 2011, Orlando, Florida

The detection of different manoeuvres performed by vehicles on highways is an important prerequisite for Collision Avoidance and Collision Mitigation systems. This paper describes an algorithm which is able to distinguish between lane keeping and lane changing manoeuvres even in curves. The approach is based on an Interacting Multiple Model (IMM) filter which also takes into account information about the course of the lane. By modeling the driving behavior of a vehicle on highways as a hidden Markov process, the maneuvre probabilities can be derived from the IMM filter results. As this problem is highly nonlinear, Unscented Kalman Filtering is used in order to avoid analytical linearization. The system is evaluated using a microscopic traffic simulator.

Chemnitz University of Technology

Presented at the ITS America Annual Conference and Exposition, November 16-20, 2008, New York, New York