STC and TSandT furnish custom lane control system for Walter Reed Medical
Center II
TEMPE, AZ - 04/04/2012 - STC has furnished a specialty AC-powered system for industrial/facility
traffic control. The project: a lane control system for the two gates on the
new Walter Reed Medical Center II located adjacent to Bethesda Naval
Hospital in MD. The project included 14 lane control indications, all
12-inches with a red X and green arrow in the display. All control is done
with a custom lane control unit which includes a color touch screen for
management of the system.
As one enters the facility through the main gate, there is a span wire
assembly with four double-sided 12-inch lamps. The user then approaches an
entry gate structure and is faced with four additional lane control signals
on both sides of the structure. As the user leaves the entry gate onto the
facility, the road narrows by one lane and there is another span wire
installation with three back-to-back 12-inch signals.
All signals show one of three states: solid red X, flashing red X or a green
arrow depending on the operating state of the gate. In standby mode, lanes
which are open will show a green arrow; lanes which are closed will show a
red X. Lanes open for entry will show a red X on the back side of the green
arrow thus allowing traffic to flow in only one direction. One lane is
configured as an exit lane in standby and shows a red X to the entering
traffic and a green arrow on the back side to exiting traffic. One lane is
red in both directions in standby as traffic volume does not warrant all
four lanes passing traffic in the standby mode. In standby mode two lanes
are set as entry and one as an exit.
There are two peak flow periods. One in the morning and one in the evening.
During the AM rush three lanes are set as entry lanes. Since two lanes are
normally entry lanes, the third closed lane changes to an entry lane showing
a green arrow to entering traffic. Since the lane started out as a closed
lane, there is no transition period necessary. The AM peak flow mode is
triggered by an output from a nearby traffic control cabinet via a 120VAC
signal. The AM peak flow mode can also be invoked through a
password-protected button on an override screen. Override mode allows
operation in only for 30 minutes and the system reverts to the standby mode.
At the end of the AM peak flow, the third entry lane changes from a green
arrow to a flashing red X. This mode indicates to users that the lane will
close shortly and vehicles should not queue up for entry to the facility.
Upon a pre-programmed time interval the lane changes from flashing red X to
a solid red X indicating the lane is closed.
The PM peak mode is more complex as some lanes transition from entry to exit
and back again. In standby, there are two entry lanes, one closed and one
exit. During PM peak most cars are exiting the facility so three lanes
become exit lanes. The standby entry lane transitions from a green arrow to
a flashing red X. Once the flashing interval is complete, the lane goes into
the red clear transition mode. Each mode can last a minimum of 60 seconds
and can be adjusted to as long as 90 seconds on a password-protected screen.
During the red clear period an override button is enabled on the lane status
screen allowing an operator to press the button and lengthen the red clear
interval if needed. Once the red clear interval is complete, the lane
changes to an exit lane showing a solid red X to entering vehicles and a
green arrow to exiting vehicles. A similar transition occurs at the end of
the PM peak when two of the exit lanes transition back to a closed lane in
standby and an entry lane.
The project required a custom control to manage the functions and to
interface to the traffic control cabinet which is located at the guard
station at the main entry. The control included programmable logic with a
custom program along with a color touch screen display with multiple levels
of information, some with password protection to limit access. STC designed
the system to have an All Red override condition in the event of an
emergency so all lanes can be closed.
A second system configured for use on a three lane gate was also provided to
the Navy for the facility. The sale of the equipment and local support was
provided by Traffic Systems and Technology of Manassas, VA. Installation
work was completed by Dynalectric of VA.
Traffic Systems and Technology has provided quality products in the traffic
and lighting markets since 1984 and operates as a manufacturer's
representative and a distributor. For more information: www.tsandt.com
Celebrating our 11th year designing and manufacturing solar-powered traffic
control systems. For more information on STC's products and services, please
stay here on our website or send an email to info@solar-traffic-controls.com
or call 480.449.0222.
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