Study the surrounding area for topographical encumbrances and radio interference when deploying wireless communication projects for traffic and parking management.
The Chicago, Illinois experience in implementing advanced parking information systems to increase customer satisfaction and improve traffic operations.
This technology has sufficed with the exception of a few minor problems experienced initially due to streetlights interfering with the system line-of-sight. Interference could have been a more significant problem had the team not conducted a Radio Frequency Field Study prior to deployment. This study detected some unforeseen field conditions which resulted in unexpected costs to the project. It was found that a highway vehicle weigh station located in close proximity to the communications tower would cause radio frequency interference. To address this problem, repeater poles were installed to provide an uninterruptible, seamless wireless communication link between the various system components. Although additional costs were incurred, the Chicago Regional Transportation Authority (RTA) and Metra identified the source of the interference early enough in the construction process to enable them to undertake corrective actions that would minimize the cost and time impacts. It is expected that costs would have been higher if the issue had been discovered after the system was in place.
The evaluation of Chicago's advanced parking information system provides the following valuable insight for other agencies considering deployment of similar ITS technologies:
- Expect that topographical encumbrances and other radio transmission interferences could require additional equipment and result in higher costs to achieve full communications capability. In the case of the RTA/Metra project, a requirement for a Radio Frequency Field Study was specified as part of the contract with the General Contractor performing the system installation and testing, and this study did uncover obstacles. Identifying these challenges early in the design process allowed the team to modify the design early on, and avoided surprises later.
- Be aware that unique capital requirements resulting from unforeseen field conditions are quite a common reality for ITS applications. Despite the fact that the Chicago project team conducted a field study prior to system design and installation, they still experienced a few minor problems initially due to streetlights interfering with the system line-of-sight. Installation of repeater poles solved this problem, but was an added unexpected cost.
Author: J. Rephlo (SAIC), R. Haas (SAIC), L. Feast (SAIC), D. Newton (SAIC)
Published By: USDOT ITS JPO, RITA
Source Date: 9 May 2008
EDL Number: 14432
Other Reference Number: FHWA-JPO-08-052URL: http://ntl.bts.gov/lib/30000/30500/30588/14432.pdf
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