Home >
Texas Highwayman Pages > San Antonio Freeway
System > TransGuide
(TransGuide logo used by
permission)
TransGuide is San Antonio's
inter-agency Advanced Transportation Management System. When it went online in July 1995, it
was the first system of its kind in the nation and it continues to be a
leader in Intelligent Transportation Systems (ITS) technology. Now operational on 93
miles of freeway, the
system will eventually cover almost 300 miles of freeway in the San
Antonio area.
Below is a map of TransGuide's
current coverage area. The green areas are currently online;
orange areas are currently under construction.
The original 26 mile section
consisting of the freeways around downtown went online on July 26th, 1995. The
sections on US 281 north of St. Mary's, Loop 410 west of I-10, and
I-10 between Fulton and Wurzbach went online in early 1999. The
sections on I-10 north of Wurzbach, Loop 1604, and Loop 410 east of
I-10 went online in August 1999. The section on I-35 between New Braunfels
Ave. and Walzem went online in March 2000, and the section
between Walzem and Starlight Terrace went online in August 2000. The US
90 segment, west of Zarzamora, went online in June 2001. The section
on I-37 near Loop 410 went online in May, 2002. The segment on I-35
north of Starlight Terrace and on Loop 1604 west of I-10 was completed in April
2003.
The following sections are currently under construction:
- Loop 410 from Ingram to Culebra
(Part of freeway widening project)
- US 281 from Basse to Nakoma
(Part of US 281/Loop 410 interchange project)
- I-35 from Loop 1604 to
Comal/Hays county line (Another project by TxDOT's Austin
District will extend installation of ITS equipment from the
Hays/Comal County Line to Slaughter Lane in South Austin.)
The following sections are
currently scheduled for construction in the next few years:
- Loop 1604 from NW
Military to Nacogdoches
System components
TransGuide uses various
technologies to detect incidents and warn motorists. The system is
composed of the following major components:
- Dedicated divergently-routed fiber-optic
rings and associated communications equipment
- 2,519 inductive loop, acoustic,
or video-recognition
traffic detectors at 220 locations
- 140 remote-controlled, full-color
video cameras
- 207 mainlane and frontage
road Dynamic Message Signs (DMSs)
- 766 Lane Control Signals (LCS)
- Three-story Traffic
Operations Center
(TOC)
- Distributed
computer system, specialized software, and related equipment
In addition to TxDOT, the San
Antonio police, fire, and EMS dispatchers are located at the TOC, as
well as dispatchers for VIA Metropolitan Transit. This allows
seamless coordination with these agencies during major traffic
incidents. The TOC is located in the southwest corner of the
I-10/Loop 410 interchange on the northwest side.
TransGuide transmits a loop of
live video images from its cameras on UHF channel 54. The City of
San Antonio's public access channel (Time Warner cable channel 21)
simulcasts this broadcast during morning and afternoon rush hours.
How it works
The system is designed to locate
incidents within two minutes and then warn motorists within 15 seconds. Here is how it works:
- The traffic detectors located in
each lane at ½ mile intervals measure traffic volume and speed in
20-second rolling averages. When a sudden or unusual change in volume or
speed is detected, the system alerts personnel at the TOC.
- Upon receiving an alarm, operators
activate the nearest camera to determine the cause of the alarm. The operator enters
information about the incident (type of incident, lanes obstructed, and
traffic data) into the system which then searches through a database of
over 30,000 scenarios and selects a corresponding response plan
based on the situation. Police and fire dispatchers located at
the TOC also use the cameras to determine which emergency services
to dispatch.
- This response recommends what
changes should be made to DMSs, LCSs, and other equipment. These changes
are presented to the operator for review and, upon approval, the system
executes all the changes within 15 seconds. TransGuide can also change
the timing of traffic signals along the access roads and major surface
arteries if traffic is forced to divert because of a freeway closure.
DMSs give text-based messages
alerting drivers to incidents or congestion ahead or on an intersecting
freeway. LCSs display one of the following symbols to guide motorists
into the appropriate lanes:
Obeying these signals is
important. Failure to do so causes increased congestion at best and
additional accidents at worst. Also, state law requires motorists to
obey them. A recent survey showed about 80% compliance with LCS
and DMS messages.
Benefits
Through the years, several studies
have proven TransGuide's benefits to San Antonio motorists in the form
of reduced secondary collisions, mitigated congestion due to expedited
incident clearing and driver information, and, most importantly, lives
saved. Here are some hard stats from one report that did a
before-and-after study of the first phase of TransGuide:
- 41% reduction in crashes
- 20% reduction in
response times to incidents
- Annual savings of $1.65
million in time and fuel
- 2,600 gallon fuel
savings per major incident
- Increase in driver
compliance to posted instructions from 33% to 80%
Source:
http://www.itsbenefits.its.dot.gov/its/benecost.nsf/0/6653718EFFE52A5C852569610051E27F?OpenDocument&Query=BApp
The future
TransGuide has been a leading
innovator in the ITS field for over a decade. In the future,
TransGuide will continue to develop and implement new technologies to
improve traffic management. Besides continued physical expansion
of the system, other plans for TransGuide are:
- Toll system integration:
TransGuide will be fully integrated with San Antonio's proposed
tollway system.
For example, TransGuide would display travel time comparisons
between tolled and non-tolled lanes to help drivers make informed
decisions on the best route to take.
- 511 service:
TransGuide is planning to implement a local 511 telephone traffic
information service. 511 is the national standard telephone
number for such services.
- Highway Advisory Radio:
These special radio stations broadcast information about localized
traffic conditions and will be especially helpful for through trucks
on the I-10 and I-35 corridors.
- Interregional
communication: With most major metro areas in Texas now fielding
ITS systems, it's time to start connecting these islands of
information together to improve traffic management between cities.
For instance, coordination between TransGuide and the Austin ITS
will make traffic information along the I-35 corridor seamless.
- Emergency management:
Continued improved coordination between TransGuide and San Antonio's
Emergency Operations Center will help facilitate better response and
operations during local emergencies, hurricane evacuations and
issues related to homeland security.
Photos
 |
Above: Frontage road DMS
Left: Closed-circuit
camera |
Above: Freeway
mainlane DMS
Above: Lane control
signals
Above: Operations
Center (inside)
Above: Operations
Center (outside)
Additional information
|
