Intelligent Roadway Information System (IRIS)

As-Built System Design Document

Prepared By

TABLE OF CONTENTS

IRIS Software Overview.................................................................................................3Basic Product Information Sheet...........................................................................3Software Features.......................................................................................................5Compatibility with Devices.......................................................................................5

IRIS System Design and Description........................................................................6Field Device Interface................................................................................................7

Traffic Sensors........................................................................................................7DMS Devices............................................................................................................7Lane Control Signs and Flashing Beacons.....................................................8Closed Circuit Television (CCTV).......................................................................8

Internal Interfaces.....................................................................................................10IRIS Server..............................................................................................................10IRIS Database.........................................................................................................15IRIS Client Application........................................................................................15

External Interfaces....................................................................................................22Traffic Data – Data Archiving and Analysis System....................................22Condition Acquisition Reporting System (CARS).......................................23IRIS TESLA.............................................................................................................24IRIS Traveler Information Application.............................................................25Digital Video System............................................................................................26VSAS........................................................................................................................26

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IRIS Software Overview

Basic Product Information SheetIntelligent Roadway Information System (IRIS) is an integrated software system that allows local and regional transportation management agencies to monitor and control dynamic message signs, traffic cameras, and ramp meters and provides access to congestion information for freeways and local arterials. An easy-to-use graphical user interface allows the operator to view data, devices and traffic information in a geo-specific representation.

A traveler information module provides a real-time traffic web site with still video images for the traveling public, streaming video for select agencies and dynamic message sign interfaces for dissemination of traffic information to the public. Data sources include road data from freeway traffic sensors and traffic events, incident and weather information from the Condition Acquisition Reporting System (CARS).

IRIS interfaces with a variety of video cameras, freeway sensors, dynamic message signs and ramp meters for both data retrieval and device control. Information, status and control are presented to the operators in an intuitive, graphical environment and are customizable to meet their needs. An electronic, GIS-based map of the project area is displayed at the startup, giving real-time roadway information and convenient point and click assess to critical functionality. IRIS software provides visual status of the system at all times. A log of the system status and actions taken is also maintained.

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IRIS Software Integrated Features

1. GIS Based Mapping2. Graphical User Interface3. Intuitive Menus and eHelp Screens4. Roadway Congestion/Speed Monitoring5. Color Coded Congestion Maps6. Travel Time Calculations7. Analog Video Switch and Camera Control8. Digitized Video Feed and USB Joystick for Camera Control9. DMS Control10. Ramp Metering Control and Configuration11. User Definable Parameters12. Signal System Detector Data13. NTCIP and Serial Communication Protocols14. Device Maintenance/Work Order Module15. Extensive Reporting Facility

Incident Management

1. Interagency Incident Data Integration2. User-Definable DMS Messages3. Ramp-Metering Control4. Amber Alerts5. Centralized Region-wide Incident Database

Advanced Traveler Information System

1. Internet Traffic Map2. HTTP site with Real-time traffic data3. Snapshots of traffic conditions4. Ramp Metering Algorithms5. Interface to third party programs

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Software Features

IRIS is built on client-server architecture and is highly modularized for scalability and inter-operability. Data and messages are managed and distributed on a real-time basis and status updates are pushed to all clients with a minimum of network traffic and high reliability.

The IRIS software has been developed in-house by the MnDOT TMC staff using open source code development techniques, and therefore no royalties or licenses are needed to operate the system or expand its use to additional consoles or users.

The primary software features of the IRIS are listed below:

Server Operating System: LinuxClient Operating System: Linux, MS WindowsProgramming Language: Java 1.5, Python 2.3 scripts, CCompilers used: Javac, GCCDatabase: PostgreSQL 7.4Web server: Apache, Tomcat 5.xGIS Maps: Arcview map filesClient Configuration Management: Java WebStartSource Configuration Management: Mercurial Repository

Compatibility with Devices

IRIS is compatible with the following types of devices and device vendors.CCTV Cameras:

- Pelco- American Dynamics

Video Switcher:- Vicon

DMS:- Ledstar - Skyline- ADDCO

Traffic Sensors:- Wavetronix- Canoga (including speed loop pairs)

Ramp Meters:- 170 controllers

Flashing Beacons:- 170 controllers

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IRIS System Design and Description

Figure 1: MnDOT Traffic Management System Software

This diagram shows a high level overview of the major components in the MnDOT Traffic Management System software IRIS and its interfaces. The next sections will describe each module in detail. A detailed diagram of the IRIS system is attached in the appendix.

The major components of the software can be loosely categorized in the following three categories:

1) Field Device Interface: Traffic Sensors, Ramp Meters, DMS, Lane Control Signs2) Internal Interfaces: IRIS Software server and client applications3) External Interfaces: Traveler information, Traffic Data, Logging and

Maintenance records, Camera Control, CARS, TESLA

Field device component describes IRIS interface to the different devices on the field.

Internal interfaces list the major IRIS software modules in the IRIS server software and client software and detail the interactions between them.

External interfaces interact with programs that are not a part of the IRIS software. IRIS either collects data or provides information or video feed to these external applications.

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Field Device Interface

Traffic Sensors MnDOT freeways have over 2000 installations of traffic sensors from Wavetronics and Canoga vendors at roughly half mile increments along majority of the freeway miles. The traffic sensors monitor each lane of travel; nearby sensors are aggregated into traffic sensor reporting sites. All these devices are connected serially over the MnDOT fiber network.

IRIS server software collects volume and occupancy data from the detectors in 30 second bins from the Wavetronics microwave detectors and Canoga loop detectors. The detectors are connected to Model 170 controllers for data collection and device control. The MnDOT system has about 500 Model 170 controllers. The IRIS system also has 6 detectors that collect traffic speed information twice a second. The IRIS server software has an additional module that has the capability to collect and store speed data from these detectors.

The IRIS server application collects, processes, archives and makes the traffic flow data available as needed. It processes and creates real-time Extensible Markup Language (xml) data files. The IRIS client application and other client applications access these real-time xml files for use in various functions. For example, the IRIS Client application graphically displays the detector volume and occupancy data on the MnDOT map. Detailed discussion on this module is located in the IRIS Server applications section.

Ramp MetersMnDOT has deployed 100 three headed ramp meters installations controlled by Model 170 controllers. Proprietary MnDOT protocol software runs on these Model 170 controllers allowing the ramp meters a combination of automated control in response to real-time traffic conditions and manual control.

The IRIS server application collects the real-time status (30 second data poll) information that is displayed on the IRIS clients. Traffic administrators also have the capability of entering ramp geometrics and ramp meter time/day information using the IRIS client application. The Model 170 controllers calculate ramp metering rates using operator given parameters. When the rates need to be changed, the IRIS server sends out a ramp meter operation object and puts it on the serial line queue.

DMS DevicesDMS devices are controlled through serial connections over the MnDOT fiber network. MnDOT has, at present, 83 DMS device installations from three different vendors. The highest numbers of installations are from Ledstar, about 60 installations. In addition, MnDOT also has 18 Skyline DMS and 5 ADDCO installations. DMS control is integrated with the IRIS software and uses the

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National Transportation Communication for ITS protocol (NTCIP). Slight variations of NTCIP have to be used for different vendors.

The IRIS client software gives operators the capability to view, create, edit and activate messages on the DMS signs. The software also has the functionality to send out “Amber Alerts” to all DMS on the system.

The IRIS server software is in constant communication with all the DMS and collects status information which is then displayed on the IRIS client software maps.

Lane Control Signs and Flashing BeaconsLane Control Signs and Flashing Beacons are connected to the system through serial connections over the MnDOT fiber network. Model 170 controllers are used to communicate with these devices. The IRIS server software polls these devices on a regular basis and provides the input to the IRIS client software for device status display.

Closed Circuit Television (CCTV)Analog video from the CCTV comes to the Regional Traffic Management Center (RTMC) through serial connections over the fiber network. The IRIS system has 380 cameras on Twin Cities regional freeway system at present. Analog video is fed into the 80 plus encoders located at the MnDOT server room. The digitized video feed is then available on the MnDOT Ethernet and is used by the IRIS client application and web page application for snapshots and Mpeg streaming video.

The analog video feed goes into the Vicon video switch. The Vicon video switch has 512 in and 256 out connections. Analog video feeds into the MnDOT RTMC monitors and the Police Dispatch Center monitors. A few analog feeds are also sent to the media.

The IRIS system has CCTV from three different vendors: Pelco, Vicon and American Dynamics (AD). At present the camera control commands go through the Vicon switch. While Pelco cameras can be controlled by Vicon commands, for AD cameras, a conversion box is need to translate Vicon commands to AD protocol.

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Figure #: CCTV Interface Diagram

In the future, this camera control process will be managed by a software module named “Protozoa”. This module will take in serial camera control commands both from the video switcher and the IRIS client software and send out Vicon, Pelco or AD control commands in the respective protocols to the cameras. This will make the software very modular since any CCTV vendor or switch can now be integrated with ease without using protocol conversion boxes. This module has been developed in-house by the MnDOT RTMC software development team and is in the testing phase at present.

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Internal Interfaces

IRIS ServerThe IRIS server hosts most of the back-end applications for the IRIS software. These back-end applications are listed and described below. The following software development tools and platform are used for development:

Operating System: LinuxSoftware Platform: Java 1.5

All the major IRIS back-end processes or threads are discussed in this section, not just the ones that run on the IRIS server. More than one server may be needed to run all these applications.

Following is a list of the major server modules and their descriptions:

Data Server ModuleOne of the main functions of the IRIS server software is to poll the field devices for status and traffic related data. The most visible and obvious use for the system is to provide a snapshot of current traffic conditions on the freeways. The IRIS data server collects a complete snapshot of the traffic on monitored freeways that are updated every half minute (30 second polling cycle). The IRIS server has various threads for the different field devices that collect traffic data and write the data to a binary file. The binary file is zipped at the end of day and SCP’D to the data servers (TRAFDAT).

The IRIS system archives and stores all loop detector information for future queries. IRIS offers an internet based tools (Data Plot and Data Extract) to

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internal users such as MnDOT employees and external users such as traffic consultants, allowing them to request volume/occupancy/speed reports for stretches of road and particular time periods. This information proves useful for design, analysis, traffic modeling and research. The IRIS system provides very sophisticated tools for archive and retrieval features to meet the needs of the Mn/DOT RTMC and roadway design groups, the University of Minnesota and other related agencies.

CCTV ControlPROTOZA is a new software module, under development by MnDOT developers that will be used for CCTV control. Operators can perform camera control actions by using the joysticks that are connected to the video switch or by using USB joysticks that will be connected to the IRIS client workstations. This module is connected serially with the Vicon video switch and the IRIS server.

Development platform: Linux, Programming Language: C

The IRIS client software sends the USB joystick commands to the IRIS server software. The server software creates a serial packet and sends it to PROTOZA which will then send it on to the right CCTV in its respective protocol. A configuration file will reside on the server running PROTOZA with the mapping for the ports.

The advantage of this piece of software is that converter boxes are not needed to change protocols. The PROTZOA software module will send the commands in the respective CCTV protocols.

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DMS ControlThe IRIS system performs all communications and control with the DMS signs using NTCIP standards. The IRIS server communicates with the signs to relay commands to post messages to the signs, query the signs for existing messages as well as query to obtain status information from the signs. (Detailed description - check the software code comments)

Ramp Meter AlgorithmsAs volumes build on the freeways, the ramp meters control the entry of vehicles to allow single car entries spaced evenly apart, rather than clusters of vehicles merging into traffic. The intent is to regulate the flow of traffic onto the freeway to minimize turbulence in freeway traffic and to maintain a steady flow of traffic on the primary freeway in exchange for small queues at various meters at the approaches.

The IRIS server uses the loop detector data to run algorithms that control ramp metering rates. Therefore, with little operator intervention, increases in volume and reductions in speeds can trigger ramp meters to activate and adjust timing as appropriate. Manual overrides are available to operators to select timing patterns as needed.

Both the volume and speed of the freeway as well as the queue length at the meter are considered in the algorithm that determines the ramp meter cycle time. The system no longer restricts traffic such that extremely long queues build up on the ramps during severe traffic slow downs.(Detailed description - check the software code comments)

Travel Time Calculation ModuleThe freeway network is processed as a connected set of nodes, or interchanges. Each interchange may have any number of entrance or exit ramps to access the network all part of the same interchange. Each ramp on the network is associated with a corridor, which is one direction of a freeway. Each access ramp and mainline station has an associated coordinate pair. Also, the static xml data contains the ordering information for ramps and stations for each corridor. The steps to calculate travel time are as follows:

1. Select origin and destination interchanges 2. Determine route(s) using a pathfinding algorithm, using interchanges to

link corridors together 3. Calculate travel time for each route (see below) 4. Choose best route 5. Present travel time and route to user

The steps to calculate route travel time are as follows: 1. Split route into corridor trips at freeway interchanges 2. Estimate travel time on each corridor

Corridor Trip Detail

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1. Create list of all segments from station upstream of corridor origin (entrance) to station downstream of corridor destination (exit)

2. Calculate distance in miles along corridor for each segment (using distance from one UTM point to the next segment)

3. Calculate running average and running low speed for each station 1. Apply speed limits to each detector speed 2. Average speed is average of all valid detector speeds 3. Low speed is minimum of all valid detector speeds 4. Average last four intervals (2 minutes) 5. If < 25 mph, extend to last six intervals (3 minutes) 6. If < 20 mph, extend to last eight intervals (4 minutes) 7. If < 15 mph, extend to last ten intervals (5 minutes)

4. If distance between any two consecutive valid stations is greater than 1.5 miles: ABORT (data not reliable)

Link Detail5. Split distance between each consecutive (valid) station into three

equal-length links 1. First link uses speeds from upstream station 2. Second link uses average of upstream/downstream speeds 3. Third link uses speeds from downstream station

6. Split the links at entrance and exit point 7. Split the link at one mile before exit point 8. Estimate travel time for each link from entrance to exit point

1. Divide link length (mi) by link speed (mph) to get link time (hours)

2. Use low speed within one mile of exit (turning penalty) 3. Otherwise, use average speed

9. Add link times to get corridor travel time 3. Add turning delay for each freeway interchange

1. Turning delay assumed to be 1 minute 2. May be refined in future

4. Calculate maximum displayable travel time 1. Find total route length (miles) 2. Divide total route length by minimum overall speed (15 mph) to

get maximum travel time (hours) 3. Convert maximum travel time to minutes, rounding up to the next

5 minutes (5 * ceil(hours * 12)) 5. If travel time > maximum displayable time, use OVER x MIN style

message

Amber Alert (DMS Module)(Detailed description - check the software code comments)

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IRIS DatabaseThe IRIS traffic management system (TMS) database utilizes PostqreSQL 7.4 Database that runs on Linux operating system. Most of the IRIS system configuration data are stored in this database. The following are the main IRIS databases that reside in the PostgreSQL:

- TMS database: These database tables contain the device and other system configuration files.

- Log database: All activity logs are stored here. Examples of IRIS logs include device activations, device communication errors, and detector malfunctions.

- TESLA database: TESLA application database is also maintained here.- Video switch database: Port numbers and the corresponding CCTV

inputs and output data are stored here. This database is used by VSAS application

Database backup is done by a backup module that creates backup files every 24 hours and stores them at both onsite and offsite locations. Using the PostgreSQL database is a hard dependency of the IRIS Software Application. This means extensive software changes will have to be made if the database needs to be changed.

IRIS Client ApplicationThe IRIS client provides the front end interface to the IRIS application. The IRIS client application is a multithreaded Java application. Users are authenticated to an LDAP (Lightweight Directory Access Protocol) system over an SSL connection from the client. This is in process of being migrated to server side authentication to an LDAP server with an SSL connection between client and server. This change will allow customizable fine grained access to the application.

Software configuration management is done using the Java Webstart application. At the IRIS client launch, a check is made using the Java Webstart application to make sure that the latest files are on the client machine. This ensures that each client launches the correct version from the IRIS server. The Java Network Launch Protocol (JNLP) file is used for this purpose.

The IRIS Client application has the following major software modules:

TrafMap Module:The mapping module is responsible for integrating static ArcView Maps. Mapbean is used for actually drawing the map. New maps can easily be added using this module.

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DDS Module:XML data interface (need more information here from software code comments)

Adding and Deleting Field Devices:Adding and deleting field devices are done through the database device configuration files. This increases the portability of the software since only those devices that are relevant to the system are entered in the database.

Only administrators have the access to this functionality.

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DMS Front-EndThe IRIS client applications allows operators to graphically view all locations of DMS signs, and by selecting signs, users may select from pre-canned phrases to build three-line messages to be displayed on the signs. A security feature allows operators to only select from pre-saved messages, and mandates that only administrators may enter new phrases into the system.

The user interface allows operators to click on any sign and view the current status of the sign as well as the current message displayed.

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Ramp Meter Module:The IRIS user interface allows operators to view ramp meter status (on, off, non-functioning) and select those meters that they wish to manually control. Similarly, patterns may be implemented for groups of ramp meters, activating pre-designed plans for groups of meters, rather than selecting each one individually.

The ramp meter configuration module also provides a front end to the users to configure the geometrics of the ramp meter and also the timings/days. The users have a GUI based application to configure the ramp width, number of lanes etc.

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Incident ModuleThis module collects the incident data from CARS and lists the incident information and a brief description. This module also plots the incident on the map. Operators can click on the incident icon to reveal 1, 5 and 10 meter radius circles to determine which DMS signs may need to be activated.

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Lane Control Signs:(Need access to software comments or description)

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Camera Module:IRIS operators may control cameras using joystick control to pan/tilt/zoom the cameras. The IRIS system allows for the full motion video to be displayed on screens within the RTMC. Since the Minnesota State Patrol and MnDOT maintenance personnel are collocated within the RTMC, certain CCTV channels are reserved for shared access by these other agencies.

(Need access to software code comments or description)

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External Interfaces

Traffic Data – Data Archiving and Analysis SystemThese tools are used for analysis of historic data and up to minute data. Data extract and data graph tools are used.

IRIS –TRAFDAT:Interface Definition- IRIS supplies traffic data to this system- IRIS writes traffic data to binary file in traffic file format- Files are accessible to TRAFDAT services and are made available to

various tools

TRAFDAT Data Tools:Interface Definition

- http request for file or list of dates for the year for which data is available- Response is the binary (unparsed) file for a given detector on a given day- Data Tools are responsible for parsing the file

Interface Description:There are two different TRAFDAT servers that receive traffic data from IRIS server – internal and external. All archive data is made available to the servers up to 5 mins age. The internal TRAFDAT data server picks up information that is up to 5 minutes old. The external TRAFDAT server that resides in the MnDOT

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DMZ receives the data file from the previous day. These TRAFDAT servers run application written in Java running in Tomcat Servlet engines on the Linux operating platform. Three main client applications utilize data from these files:

1) Data Plot: Java application2) Data Extract: Java application3) Traffic Plot: Python application

The internal TRAFDAT server stores information for the internal users of the system such as IRIS client applications and intraweb users. The main role of the external server is to serve the data out to the public using a web server. The external server is hence located in the MnDOT DMZ.

Based on the user requirements, the IRIS system has over the years generated various types of reports with various levels of detail and time length. IRIS has a very sophisticated repertoire of reports and data analysis tools.

Condition Acquisition Reporting System (CARS)Event/Condition Reporting System (CARS) maintains and disseminates information about road/weather conditions, events such as road maintenance, crashes etc. CARS data sources include MnDOT RTMC operations personnel and other departments such as road maintenance and the construction departments; the commercial vehicle permits department, etc. CARS data is used as the basis of the Minnesota 511 traveler information system and website application. As it relates to IRIS, CARS provides incident data.

Figure #: C.A.R.S Interface Diagram

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IRIS – CARS Interface:- IRIS consumes data from CARS, it sends a http request for XML

document defining all event- IRIS filers XML document based on definable policy and processes events

Interface Description:The CARS system periodically writes out an incident XML data file. This file is read by the IRIS client application to display the incidents on the GIS map and their details. The incident XML file is also read by the WEBDOCS application which is responsible for publishing the incident data for the traffic website.

The Minnesota State Patrol sends filtered incident data to RTMC operators, who review the data and locate the incidents via the CCTV system. Filtering is performed on the data so that only those incidents are picked up by IRIS that have potential traffic impacts. For security reasons no personal or confidential information is downloaded from the file.

CARS also ingests loop detector data provided by IRIS thru their Traveler Information Website and by processing a set of algorithms, automatically creates situations that are served up on the 511 phone system, allowing callers to 511 to hear such reports as “stop and go traffic on 1-35W from Highway 42 to the Minnesota River” without any operator intervention.

IRIS Traveler Information Application

This application provides real-time traveler information via the web. It provides data and data/system definition in a standard way so that third party developers can easily develop to it. There is no real developer’s API required, developers can just get the files and parse them to get meaningful data.

Figure #: Web Interface Diagram

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IRIS – WEBDOCS Interface- WEBDOCS connect to IRIS as a client via RMI connection and receives

all updates as any client- IRIS supplies data to this system

WEBDOCS – Website Interface- WEBDOCS FTPs files to web server on a regular basis.

Interface DescriptionWEBDOCS (Web Based Document Conversion System) application gets data from the IRIS server to create real-time documents such as traffic map, freeway link travel time. It also gets data from the CARS generated XML file for freeway incident data. These data documents are picked up by the FTP Engine and sent to the MnDOT web server. The MnDOT web server resides in the MnDOT DMZ.

The traffic flow map with real-time loop data is produced and published every 30 seconds. The traffic flow map is color coded for ease of use, identifying slow downs by coloring the roads red or yellow.

The WEBDOCS application is an Apache Tomcat 6.x application, written internally by MnDOT software developers for performing this specific functionality.

Digital Video SystemVideo System provides Motion JPEG streams to IRIS Client and to media partners/respondents that don’t have the resources to afford full motion analog video. This module also provides snapshots to general public, currently supports updates every 10 seconds (this interval is configurable)

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IRIS – Digital Video Interface- HTTP request for stream from IRIS client to video backend- Backend response is MnDOT implementation of multi-part HTTP

response (content is essentially MJPEG)

Interface DescriptionAnalog video from the field CCTV cameras is brought in to the center through the fiber network. CCTV 4 port encoders are used at the center to convert from analog to digital feed in form of single jpegs and mpeg streams and made available on the MnDOT Ethernet network.

The video back-end application runs on a dedicated video server and is responsible for providing video images to the Video front-end program. The video front-end program resides on the video server in the MnDOT DMZ. Images are cached on the MnDOT server and served out to the general public. These images are updated at configurable intervals (10 seconds at present). The image is requested from the video back-end program only once and cached on the MnDOT video server.

VSASVSAS Admin ToolVSAS HyperStreamCamera Selector

IRIS TESLAThis TMS Equipment Status Logging Application (TESLA) is the device maintenance tracking application, also responsible for generating work orders. TESLA has a separate database that also resides on the IRIS server.

(Need screen shots, access to software or description)

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APPENDIX

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