Cross-cutting Issues

the I-95 corridor, known as 95 Express. The FDOT had developed a software application to
implement dynamic pricing, which has shown to be an important element in reaching the
project’s goal of providing more reliable travel options along the corridor. The 95 Express has
provided transit users and motorists in both the express lanes (EL) and General Purpose Lanes
(GPL) with significant benefits. The popularity of the project has resulted in increasing demand
for the express lanes and new challenges for FDOT to provide the level of service expected by
express lane users based on existing toll rules. This paper documents an analysis of three
operational strategies. These strategies include:
--  Adjustments to the dynamic pricing parameters.
--  Congestion messaging on lane status signs when the EL experience significant
congestion.
-- Post incident pricing strategies.

Authors: Charles J. Robbins, P.E., Javier Rodriguez, P.E., Rory Santana, PE, PTOE

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

This paper will describe “lessons learned” by the County Los Angeles Department of Public Works (Public Works)  to deploy a hybrid communications system comprised of fiber, twisted wire pair, leased telephone lines and wireless radios to support the communications requirements for real time monitoring of traffic signals and closed circuit television cameras (CCTV) installed over a large noncontiguous geographical area, containing many jurisdictions, with the ultimate goal of providing an integrated solution to coordinate traffic signals and enable real time monitoring of traffic signals and CCTV cameras.

County of Los Angeles Department of Public Works

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

Managed Lanes provide an effective strategy in balancing travel supply and demand while combating congestion and offering mobility options to our travelers.  One form of managed lanes is High Occupancy Toll (HOT) lanes which are reserved for buses and designated High Occupancy Vehicles (HOV) while the unused capacity is sold off to other vehicles based on an adopted toll pricing structure.

The purpose of this paper is to provide an overview of HOT lane projects throughout the U.S.; discuss the key issues in successfully implementing them; address the specific issues associated with growing managed lane projects into system networks; and improving the reliability of transportation planning models to support the development of managed lane system networks.

Author: Dr Robert Edelstein, PE, PTOE

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

GPS position measurements are typically described by stating parameters of the statistical
distribution of the measurements of a stationary receiver (e.g. 50% CEP). However, in a
moving vehicle, typical receivers only produce a single measurement in a measurement
interval (typically one second). Conventional practice applies the distribution parameters
(error radius and confidence) to these isolated measurements. However, this approach is
incorrect since the actual position is not known, and in some instances the confidence
interval radius may imply that a position may be within the confidence interval from the
measured position when, in fact, it is twice the interval radius away. This paper explores
this phenomenon, and provides a correct interpretation of GPS position measurements in
a dynamic environment. It also explores the possibility of using the over specification of
the position, that results when more than four satellites are in view, to determine not only
the current integrity of the position measurement, but also to improve the accuracy of the
reported position measurement.

Author: Scott Andrews

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

Positioning requirements for ITS applications have typically been developed by
examining the physical geometry of the environment in which the application is intended
to operate. However, this approach does not account for the impact of statistically
distributed errors in position measurement. As a result, it is not possible to apply
conventional statistically based position accuracy specifications to these heuristically
derived geometric requirements. This paper provides a decision based approach to apply
measurement confidence intervals in the requirements development process in order to
produce statistically usable system requirements. The process involves assessing the
geometric regions where false negative and false positive positioning decisions may
occur in the context of a statistically distributed position error measurement, and then
assigning confidence based error radii based on the level of error that can be
accommodated, and the impact of such error on the performance of the application. The
result is a more systematic and defensible development of positioning requirements, and
a clear understanding of the impact of position measurement errors.

Author: Scott Andrews

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