ITE Journal April 2018 - 35
Wrap: Chalk Art
Central Avenue Streetscape Project Boundary (circa 2003)
Powder Coat Grey
Wrap: CM Russell Kid
Art (not evaluated)
Figure 1. Map showing the cabinet treatment locations.
Part 2: Temperature Evaluation with Varying
Photographs Courtesy of Research Team
There has been an industry-wide maintenance concern that
treating the exterior of the traffic signal cabinet would cause
further insulation, therefore impacting the internal components.
For this case study, in addition to evaluating artist vinyl, three
other locations with different exterior finishes were evaluated for
comparison. Temperature measurements were collected to record
variations in temperature between internal cabinet temperature and
outside air temperature before and after the artist wrap application.
As shown on the map in Figure 1, the location of the cabinet
(Artist Wrap: Chalk Art) 2nd Ave N at 4th St N.
(Powder Coat Grey Finish) 2nd Ave N at 6th S N.
(Aluminum or No Finish) 2nd Ave N at 9th St N.
(Artist Painted) 1st Ave S at 2nd St S.
The image to the left shows the exterior of the cabinet, and the photo to the
right shows the interior of the cabinet.
Two temperature gauges were placed at each traffic signal
cabinet during the same study period to monitor temperatures.
The temperature gauge on the exterior was placed on the lip of the
cabinet top. This was an inconspicuous location where the public
would not disturb it. Further, the interior temperature gauge was
placed on the traffic controller shelf of the NEMA field cabinet.
Ten measurements were recorded at each cabinet, Monday-Friday,
at various times throughout the day in April 2017. All four study
locations were exposed to full sun.
All cabinets used in the temperature variation study are
NEMA-rated cabinets. All MDT owned NEMA cabinets are accommodated with internal thermostats to set thresholds for internal
temperature. A small fan located on the internal cabinet roof is used
to cool the cabinet for the upper thermostat limit, a heater (located
on the inside door panel) for the lower thermostat reading. The
internal temperature is governed by the thermostat. Although the
cabinet thermostat is generic, the component has been proven to be
reliable in the industry. However, the thermostats cooling fan can
at times be unreliable, and this component will need to be replaced
occasionally due to dust build-up on the fan motor.
For the case study, the desired thermostat minimum-maximum
temperatures were set between 40°F to 100°F (4.4°C to 37.7°C),
respectively. When the internal ambient temperature of the cabinet
reaches a threshold, the fan-thermostat should determine when the
fan "kicks-on." The threshold settings are knob controlled, which
can make the setting accuracy challenging for the maintenance
technician or traffic engineer.
Data at each of the four sites were sampled for a period of ten
days in the spring. The temperatures were collected to see if the
w w w .i t e.or g
Apri l 2018