Life cycle cost of four options for a communications network connecting ITS field devices to the Illinois DOT District 8 Traffic Operations Center range from $43 million to $52.5 million.
The major interstates in District 8 include I-55, I-64, I-79, I-255 and I-270 and collectively encompass approximately 105 miles of centerline highway. The ITS devices that would be deployed along these interstates include closed circuit television (CCTV) camera with pan/tilt/zoom (PTZ), video detection stations, dynamic message signs (DMSs), and highway advisory radios (HARs). Technical and non-technical issues as well as initial and long-term costs were considered in the various communication alternatives. After reviewing all alternatives, four were selected as viable options and explored in greater detail. A fifteen (15) year service life was used for the life cycle cost analysis. The four communication options are summarized below. Initial capital cost, operations & maintenance (O&M) costs, and 15 year life cycle costs are provided for each option.
Option 1 – All Fiber
Option 1 calls for a fiber optic backbone with field components connected to hubs via fiber optic cable. The cameras would be connected to the hub point-to-point using low-cost modules that do not require multiplexing, and the other ITS devices would be connected together via fiber optic ring to the hub. Data from the hub would be multiplexed and transmitted to the TOC over the backbone. Data would be demultiplexed and distributed at the TOC.
The capital cost of this option reflects the high cost of installing in-ground conduit and providing a redundant (diversified) backbone. The estimated cost of equipment and installation is $26 million. Labor maintenance for 15 years is approximately $16 million plus $1 million for materials over the 15 years. The total life cycle cost for this option is $43 million.
Option 2 – All Microwave
Option 2 calls for licensed microwave for the backbone and communication link connecting the field devices to each hub. Camera images and data from the low speed ITS devices would be transmitted over allocated licensed microwave spectrum to a hub. The images and data would be multiplexed at the hub and transmitted to the TOC via microwave backbone. Images and data would be demultiplexed and distributed at the TOC.
While this option would incur a lower capital cost, approximately $18.1 million, it does require significant maintenance for path realignments and equipment adjustments. Maintenance cost for labor is estimated at $24 million plus $3 million for materials over 15 years. The total life cycle cost for this option is $45.1 million.
Option 3 – Fiber Optic Backbone
Option 3 calls for a high-speed fiber optic backbone with field device connectivity to hubs via licensed microwave. Camera images and data collected at the hub would be multiplexed onto the fiber optic backbone and transmitted to the TOC. Images and data would be demultiplexed and distributed at the TOC.
The total life cycle cost of this option reflects the high cost associated with in-ground conduit (although the field to hub connections would utilize lower cost microwave) and the significant maintenance cost associated with microwave. Capital cost is estimated at $26 million, 15 years of labor maintenance at $24 million plus $2.5 million for material over 15 years. The total life cycle cost for this option is $52.5 million.
Option 4 – Microwave Backbone with One Segment of Fiber
Option 4 calls for a licensed microwave backbone and licensed microwave connectivity between field devices and hubs with one segment to have fiber optic cable from field devices to a hub and from that hub to the TOC. This option includes the fiber optic cable segment when conduit could be installed as part of construction project or when a community would not support the installation of ~240 foot communication tower. The major segments of the (microwave) backbone function as described in option 2 while the single fiber segment would function as described in option 1. The termination point of the fiber segment would be a collector hub or the TOC depending on the location of the hub with respect to the TOC.
The costs associated with this option are in line with the costs for option 2 (all microwave), yet is slightly higher accounting for the fiber optic segment. The capital cost is approximately $19.3 million. The labor maintenance is estimated at $24 million plus material costs over 15 years at $2.8 million. The total life cycle cost for this option is $46.1 million.
At the time the paper was presented IDOT District 8 had not selected an option to implement. The paper mentions that District 8 appeared to be comfortable with all of the technology options presented in the study.
Traffic Operations Center/ITS Field Components Communication Study
Author: Siesel, Douglas E. (Iteris) and Brian A. Sneed, PE (Illinois DOT)
Published By: Paper presented to the 13th ITS America Annual Meeting, Minneapolis, Minnesota
Source Date: May 2003
Option 2: Capital Cost $18.1 million, Life Cycle Cost: $45.1 million.
Option 3: Capital Cost $26 million, Life Cycle Cost: $52.5 million.
Option 4: Capital Cost $19.3 million, Life Cycle Cost: $46.1 million.
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Intelligent Transportation Systems > Freeway Management > Information Dissemination > Highway Advisory Radio
Intelligent Transportation Systems > Freeway Management > Surveillance > Traffic
Intelligent Transportation Systems > Freeway Management > Information Dissemination > Dynamic Message Signs
Intelligent Transportation Systems > Transportation Management Centers > Permanent TMCs > Freeway
HAR, CCTV, closed circuit television cameras, road monitoring, sensors, vehicle detector, traffic detection, traffic monitoring, congestion monitoring, DMS, CMS, VMS, Changeable Message Signs, Variable Message Signs