| Congestions Management Strategies |
| Using ITS Technology to Manage Congestion at
Parking Facilities |
| By Bikash Ron Pati, Orlando, FL, 1-407-875-3337,
pati@pbworld.com |
| Sixty seconds to park your car! Sounds like an impressive
claim. Not impossible though, according to the vendors promoting products
for advanced parking management systems. |
|
One time or another, every one of us has experienced the frustration
of searching for a parking space(especially in crowded, multi-storied
facilities where floor-to-floor searching is a common occurrence.
Now, an intelligent transportation system (ITS) technology parking
guidance system (PGS) has the potential to minimize search-time by
directing motorists to vacant spaces. This technology can be effective
in managing congestion in parking facilities.
PGS has been widely deployed in western European countries, particularly
Switzerland, Germany and France. In the U.S., however, the traditional
method of dealing with congestion at parking facilities had been to
construct additional spaces. This is beginning to change, however.
For example, an advanced parking information system (APIS) has been
installed at the Orlando International Airport (OIA), shown in Figure
1. This system does not provide guidance to vacant spaces currently,
but it keeps track of the number of spaces vacant on each floor and
displays that real-time information to incoming vehicles. Installation
of this system has reduced floor-to-floor searching, but delay is
incurred as vehicles look for a space within a floor.
Figure 1: APIS Technology at Orlando International Airport
Parking |
The Basics of a Typical PGS
A typical PGS is comprised of five major components:
- Presence detectors at each parking space
- A simple wireline communication system
- Central control
- Variable message signs (VMS) for information
dissemination
- Dynamic guidance (trailblazer) signs.
The way it works is simple. Each parking space is equipped with a
presence detector that collects real-time occupancy/vacancy information.
The information is transmitted to a control room, then disseminated
to the incoming motorists by means of a CMS. Guidance is provided
by trailblazer signs that direct motorists at each decision point
to vacant spaces. Communication elements vary depending on the complexity
of the system, number of spaces being monitored and the desired reliability.
The installation cost of PGS depends on the type of hardware, software
and labor used for operations and maintenance. It has been estimated
that a basic system would cost about $350-$500 per space in the U.S.
The benefit-cost ratio of a PGS would be high because significant
reductions in delay, fuel consumption and emissions can be expected.
A preliminary study using Smart Parking Analysis Software (SPARKS),
indicates a benefit/cost ratio of 3.91, but more studies are needed
to arrive at a conclusive number.
Operation of Parking Guidance Systems
In the case of a multistory parking structure, space detectors can
be mounted to the ceiling above each parking space. A light emitting
diode (LED) signaling device on each detector indicates either a vacant
space (green), occupied space (red) or a space with parking time limit
exceeded (orange). (LEDs have a high useful life and are immune to
the fumes, dirt and vibrations that are common in parking areas.)
A VMS at the entrance of the facility may summarize vacancies for
the entire facility, allowing drivers to choose a floor based on the
number of spaces available. Informational and guidance signs may also
be placed on each floor.
For an off-street parking facility, detectors are generally embedded
in the ground. Detector information is integrated and appropriate
guidance lights are displayed. Information displayed on VMSs and guidance
signs, which is updated in fixed-time intervals, advises motorists
of the:
- Number of spaces available
- Routes to be followed, as indicated by green
lights
- Routes to be avoided, as indicated by red lights.
Although not discussed in this article, other types of detectors could
be used, especially for off-street parking facilities.
All space detectors are linked to the central control by either twisted-pair
or fiber-optic cables. Generally, a simple five-wire system is sufficient
for communications between parking space detectors and the control
room, although the communication design may vary depending on the
size and complexity of the system. The central computer polls detectors
several times a minute to obtain real-time information or identify
a detector failure.
Large parking facilities are generally divided into zones, each of
which is controlled by a decoder. The decoders, generally capable
of controlling up to 240 spaces, are linked to the central control
via the communication media. Zoning by a decoder offers flexibility
in controlling the parking facility. For example, if a parking zone
is reserved exclusively for rental car companies, the vacancy information
relayed to the signs would exclude those spaces.
Several Benefits of PGS
In western European countries, PGS has been demonstrated to be particularly
beneficial for multi-storied parking structures where searching delay
is higher. In particular, the tangible and intangible benefits that
can result from the installation of PGS include the following:
- Less delay and lower fuel consumption and
emissions due to reductions in travel time and idling
- Better use of parking capacity due to real-time
counting and guidance
- Efficient circulation due to guidance of
vehicles directly to vacant floors or areas within a floor
- Better vehicle occupancy time monitoring
for verification of time stamps on tickets, in case of disputes
- Increased safety, particularly, when CCTV
is installed using a common communication backbone
- Higher revenue due to better use of parking
spaces and higher customer satisfaction.
Discussion
Improvements to parking facilities generally receive a lower priority
compared to other transportation infrastructure such as freeways and
arterials. One reason for such disparity can be attributed to safety,
for parking facilities do not pose much of a safety problem compared
to highways. When savings in delays are factored into an economic
analysis, however, ITS investments may be justified, especially for
crowded parking facilities commonly seen at airports and in downtown
areas.
A high benefit-cost ratio and the availability of PGS technology justify
its deployment. In order to minimize cost, a PGS can be designed to
operate automatically without an active operator. The system software
can report failed detectors and communication components that should
be replaced periodically. A periodic review of the system log may
be sufficient to a basically flawless operation.
With PGS technology in place, parking becomes more efficient and faster.
Now, are you convinced that you may be able to park in about...60
seconds? |
|
Notes: Smart Parking Analysis Software (SPARKS),
was developed by the author and Dev Roy, former professor of State
University of New York at Utica/Rome. It was first distributed by
McTrans, Gainesville, Florida, in March 1995.
For a previous PB Network article by Ron on SPARKS, see Winter
‘96/97, Issue #37, pp 31-32. |
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