Design the system to withstand the demands of the physical environment in which it will be deployed.
Virginia's experience implementing a pilot automatic vehicle location (AVL) system in an urban winter maintenance operations setting.
- Consider the physical environment in which the system will be used: Snow removal activities represent the worst-case environment for testing AVL technology, such as that used in this pilot program. In snow events, temperature and climatic conditions are at their worst. GPS signals undergo serious electronic signal attenuation and noise effects because of snow on trees and emissions from vehicle radios and strobe lights. Vehicle-mounted units are subject to significant corrosion, mechanical shock, and fatigue conditions. Although all of these conditions did affect system performance, they did not preclude successful use of the technology over three winters of use.
- Focus on the design restrictions: Along with the harsh winter environment, the repetitive installation and removal of in-vehicle GPS tracking receiver and communication devices (referred to as in-vehicle units or IVUs) also resulted in a higher than expected failure rate (5 percent to 10 percent per storm) for wiring and sensor units. The unsecured units (those without a mounting board) moved around in vehicles during operations, resulting in the connecting plugs frequently being disconnected from the back of the IVU, wire breaks, display screen fractures, and antenna lead separations. The lesson learned was that since temporary installation of IVUs created problems, IVUs should be permanently installed in vehicles when possible.
As learned from this experience, system designers should take one more step in their design process and design devices so that the devices will work properly in the environment where they will be used. Additionally, assumptions that designers have made and used in the past may not always fit for devices that will be used in different environments; designing devices to fit the needs of their intended environment could lead to increased system productivity and efficiency, and increased customer satisfaction by all who work with the systems.
Author: Daniel S. Roosevelt, Robert A. Hanson, Virginia Transportation Research Council; William M. Campenni, Stuart AVL Technologies, LLC
Published By: Virginia Department of Transportation and the University of Virginia
Source Date: 4/1/2002
Other Reference Number: VTRC02-R11URL: http://www.virginiadot.org/vtrc/main/online_reports/pdf/02-r11.pdf#search='Lessons%20Learned%20From%20a%20Pilot%20Project%20of%20an%20Automatic%20Vehicle%20Location%20System%20in%20an%20Urban%20Winter%20Maintenance%20Operations%20Setting'
Daniel S Roosevelt
Virginia Transportation Research Council
Virginia Department of Transportation
Volpe National Transportation Systems Center
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Intelligent Transportation Systems > Transit Management > Operations & Fleet Management > Automatic Vehicle Location / Computer-Aided Dispatch
Intelligent Transportation Systems > Roadway Operations & Maintenance > Asset Management > Fleet Management
Intelligent Transportation Systems > Commercial Vehicle Operations > Carrier Operations & Fleet Management > Automatic Vehicle Location / Computer-Aided Dispatch
Intelligent Transportation Systems > Road Weather Management > Response & Treatment
automated vehicle location, computer aided dispatch, automatic vehicle locator, AVL, CAD, AVL/CAD