Cost

Two California cities opt to transmit real-time video over existing copper-based communications infrastructure at a cost of $96,000 compared to $161,000 if new fiber optic cable alternative selected.


May 2004
Concord; California; United States; Walnut Creek; California; United States


Summary Information

The Cities of Concord and Walnut Creek, California investigated alternatives for transmitting real-time traffic video from field devices to each city’s respective transportation operations center (TOC). During the design phase of the project, each city conducted a budgetary cost comparison to examine the capital costs associated with two alternatives:
(1) upgrading the existing network of copper wire (twisted pair) traffic signal control communications network
(2) converting to fiber optics.

Both alternatives would provide enough bandwidth for high-quality video; however, the fiber option would allow for future communications needs (i.e., internal network, DMS, etc). Although the copper wire option would have limited functionality, it would be less expensive, and enable the city to upgrade other signal system elements such as traffic signal controllers.

The table below shows the results of the pre-construction cost comparison (based on 1-mile of transmission distance).

Existing Copper
Network
New Fiber
Network
Remove Existing Cable
$10,560
Furnish and Install FO Cable
$26,400
Fiber Video Transceivers
$5,000
Video Transceivers for Copper
$10,000
Interconnect Cable Modifications
$1,000
Once the decision was made to use the existing copper infrastructure, the twisted pairs within each interconnected cable were reallocated to provide full duplex (two-way) communications between CCTV cameras and the TOC.

Both cities intended to install a combination of fixed and “dome” style CCTV cameras on existing poles and route video and camera data cables back to the traffic signal controller cabinet at each intersection. Inside the cabinet, the video cable (coaxial cable) from the camera was connected to a video transceiver and the camera control cable (two-conductor cable) was connected to an amplifier/repeater.

During the upgrade project, the City of Walnut Creek took the opportunity to repair and install additional interconnect cables to accommodate video throughout the city. They minimized the amount of transmission equipment needed by placing the equipment as far apart as possible without exceeding a 3,500 foot signal attenuation limit. In each control cabinet, video signals were transmitted onto twisted-pair interconnect cables and then re-amplified every mile (5 miles maximum depending on condition of cable) until the signal reached the head-end terminal block at the TOC. At the head-end, a receiver equipped with one video card per camera accepted the signal and transferred it to an analog video switch and video console where it could be viewed by TOC operators.

In Concord, the city opted to transmit the data digitally back to the TOC without the need for repeaters. This configuration required that protocol converters be installed at each controller cabinet, and at the TOC.

Cost estimates for each alternative were prepared from actual bids (see tables below). Only capital costs were considered. The cost of traffic control, controller upgrades, and mobilization were not included because theses costs were roughly equivalent between the two options. The two estimates assume a 5-mile corridor with cameras installed every mile beginning at the TOC.

Alternative 1: Video over existing Copper Interconnect



End of Line

Mile 1

Mile 2

Mile 3

Mile 4

Head End

Total Quantity

Unit

Unit Cost

Item Total

Camera

1

1

1

1

1


5

EA

$7,500

$37,500

RS-422 Repeater

1

1

1

1

1


5

EA

$450

$2,250

1-Channel Video Transceiver

1






1

EA

$3,250

$3,250

2-Channel Video Transceiver

1

1





1

EA

$4,300

$4,300

Rack-Mount Chassis


1

1

1

1


4

EA

$3,900

$15,600

1-Channel Rack-Mount Video Transceiver


3

4

5

5

17


EA

$1,250

$21,250

Interconnect Terminations

1

1

1

1

1

1

6

EA

$200

$1,200

Replace damaged Interconnect (assume 1 mi)






1

1

MI

$10,560

$10,560

Option Total










$95,910


Alternative 2: Video over new Fiber Optic Cable



End of Line

Mile 1

Mile 2

Mile 3

Mile 4

Head End

Total Quantity

Unit

Unit Cost

Item Total

Camera

1

1

1

1

1


5

EA

$7,500

$37,500

Video + Data Fiber Transceiver

1

1

1

1

1


5

EA

$3,200

$16,000

Video + Data Fiber Receiver






5

5

EA

$3,100

$15,500

Furnish & Install 12-Strand Fiber Optic Cable

1

1

1

1

1


5

MI

$15,840

$79,200

Make & Test Fiber Optic Splice

2

2

2

2

2

10

20

EA

$175

$3,500

Fiber Optic Splice Closure

1

1

1

1

1


5


$1,100

$5,500

Fiber Optic Cable Termination Unit

1

1

1

1

1


5


$500

$2,500

Fiber Optic Patch Cords

1

1

1

1

1

5

10


$100

$1,000

Option Total










$160,700




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Source

Real-Time Video over Copper Networks: A Tale of Two Cities

Author: Peterman, Josh, PE (DKS Associates), Rafat Raie, PE (City of Walnut Creek, CA), and Garland Wong, PE (City of Concord, CA)

Published By: Paper presented at the 14th Annual ITS America Meeting, San Antonio, Texas

Source Date: May 2004


System Cost

Video over existing copper interconnect: Capital Cost $95,910 for a 5 mile corridor.

Video over new fiber optic cable: Capital Cost $160,700 for a 5 mile corridor.

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Keywords

CCTV, closed circuit television cameras, road monitoring, sensors, vehicle detector, traffic detection, traffic monitoring, congestion monitoring

Cost ID: 2005-00094