ODOT District 4 Variable Speed Limit Signs
Status: Future
Description
Variable Speed Limit (VSL) signs are an ITS element related to Ohio's Active Traffic and Demand Management (ATDM) program that aims to increase travel time reliability on ODOT roadways in major metro areas. VSL signs in the field communicate centrally with the ODOT ATMS, and reduced speeds would be implemented either by TMC operators or can be automated based on the level of traffic detected by nearby ODOT Vehicle Detection Devices.
Stakeholders
| Stakeholder | Role | Role Status |
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| ODOT | Owns | Existing |
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Physical Objects
Functional Objects
| Functional Object | Description | User Defined |
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| Roadway Variable Speed Limits | 'Roadway Variable Speed Limits' includes the field equipment, physical overhead lane signs and associated control electronics that are used to manage and control variable speed limits systems. This equipment monitors traffic and environmental conditions along the roadway. The system can be centrally monitored and controlled by a Traffic Management Center or it can be autonomous, calculating and setting suitable speed limits, usually by lane. This application displays the speed limits and additional information such as basic safety rules and current traffic information to drivers. | False |
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Physical Standards
| Document Number | Title | Description |
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| ITE ATC 5201 | Advanced Transportation Controller | This standard defines the functionality and performance requirements for a modern ITS controller known as an ATC. It is similar to the NEMA TS–2 standard in that it defines basic capabilities but leaves hardware choices up to the manufacturer. |
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| ITE ATC 5202 | Model 2070 Controller Standard | This standard specifies the hardware for a modern, open–architecture controller for ITS applications that can run Linux and is capable of executing advanced signal controller logic, among other things. |
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| ITE ATC 5301 | Intelligent Transportation System Standard Specification for Roadside Cabinets | This standard specifies the characteristics of a modern controller cabinet for the ITS industry. |
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| ITE ATC 5401 | Application Programming Interface Standard for the Advanced Transportation Controller | This standard defines the application programmers' interface (API) that should be supported by an ATC, which is an open–architecture controller that can host multiple ITS applications. |
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| NEMA TS 8 | Cyber and Physical Security for Intelligent Transportation Systems | This specification describes how agencies and other transportation infrastructure owner/operators should implement cyber– and physical–security for ITS. |
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| NEMA TS2 | Traffic Controller Assemblies with NTCIP Requirements | This specification covers traffic signaling equipment used to facilitate and expedite the safe movement of pedestrians and vehicular traffic. |
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| NEMA TS4 | Hardware Standards for Dynamic Message Signs (DMS) With NTCIP Requirements | This standard provides hardware specifications for safe, dependable, functional, and easily maintained Dynamic Message Sign (DMS) equipment. |
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Interfaces To
(View Context Diagram)