16-01-2013, 11:30 AM
Advanced CMS Final Report
Advanced CMS.pdf (Size: 100.66 KB / Downloads: 40)
EXECUTIVE SUMMARY
In cooperation with the California Department of Transportation (Caltrans), Montana State University's Western Transportation Institute has begun development of a Changeable Message Sign (CMS) specification, the Model 700, for use by all Caltrans Districts.
In addition to and preceding this final report, four items were produced as project deliverables:
Survey of State Department of Transportations on use of CMS technology
Survey of Caltrans districts and departments on use of CMS technology
Draft Concept of Operations document
Presentation of the project at the Intelligent Transportation Society’s World Congress
This document is presented as a high-level summary, and the documents above should be referenced for further detail.
INTRODUCTION
Standardization and tight specification of technologies has been a critical component in encouraging the usage of intelligent transportation systems (ITS) across the United States. Early adopters of changeable message signs were challenged with vendors who went out of business or no longer supported their products. They were also challenged when trying to operate similar products manufactured by multiple vendors. Standardization efforts such as NTCIP have gone a long way toward addressing these problems. Nonetheless, there remains a considerable diversity of products with limited if any interchangeability between system components. This introduces training and spare parts inventory challenges for customers, and makes customers more dependent on vendors for ongoing support.
These challenges are especially acute in California which has the greatest number of CMS deployed by any state department of transportation (DOT). The California Department of Transportation has deployed changeable message signs conforming to its Model 500 specification for almost two decades. The specification is tightly defined with respect to geometric dimensions and communications protocols. As such, it supports nearly complete interchangeability between components made by different manufacturers. However, in the years since the Model 500 specification was developed, there have been many improvements in CMS technology including improvements in lighting, communications, control, reporting, and diagnostics. Consequently, Caltrans contracted with a team led by the Western Transportation Institute to develop a new CMS specification.
BACKGROUND AND METHODOLOGY
Based on results of this project and corroboration with industry, when state DOTs create a specification for Changeable Message Signs it is exclusively done with functional or performance measures. Caltrans is unique in that it creates a detailed design specification that is complete enough for multiple vendors to create a compatible product with all existing or any future signs. Also, since Caltrans owns the standard and therefore all information needed for production of a sign, dissolution of any specific vendor will not affect future availability of signs based on the specification. However, the success of the detailed design specification and subsequent stability of the Model 500 specification has allowed the industry to surpass the Model 500 specification with new features and technology.
CONCEPT OF OPERATIONS
The concept of operations document serves as a foundational document for how the Advanced CMS is operated from the perspectives of operators, maintainers and travelers. This document addresses the environment in which the CMS operates. In it can be found how the Advanced CMS displays messages, interacts with various software packages, and communicates. The document also gives power requirements, temperature ratings and similar characteristics.