ITE Journal April 2018 - 33
Photograph Courtesy of City of Great Falls Public Works Department
This case study is two-fold. First, it documents the public
involvement process to implement public art for the Traffic Signal
Box (TSB) Art Project of the City of Great Falls, Montana, USA
using an artist-vinyl wrap. Second, it provides information on
internal cabinet temperature effects using various exterior surface
treatments, including the wrap.
Part 1: Implementation of Public Art Displays on Traffic
In 2000, the City adopted an ordinance known as "Discovery
Gallery."1 This ordinance allowed the City's Business Improvement
District (BID) to create public art projects, and it identified who
needed to be included in the art selection process. Some of the
City's first art displays occurred in 2003 with the completion of the
Central Avenue Streetscape Project. The 2011 City of Great Falls
Downtown Master Plan references livability and character, in which
there is an expanded streetscape to tell a story.2 Further, a recommendation from the City's 2013 Streetscape Plan was to engage local
artists as an integral part of the Gateway design.3 Funds have been
allocated in subsequent years to use the traffic signal boxes as the
"canvas" for this art. Both documents recognized the role of public
art, and it has allowed for expansion of the TSB Art Project outside
of the BID.
Prior to 2012, most of the City's traffic signal cabinets within the
BID were painted black. As written in a 1990 National Cooperative
Highway Research Program (NCHRP) report regarding cabinet
treatments, "A painted cabinet may provide a better appearance,
if the paint can be maintained. However, colors should be light,
because dark colors will increase the internal temperature of the
cabinet significantly possibly resulting in damage to the electronic
components housed within."4 The National Electrical Manufacturers Association (NEMA) standards for traffic signal control
equipment requires controller assemblies to be able to withstand
temperatures between -30°F to 165°F (-34°C to 74°C). To protect
the cabinet components from reaching these internal temperatures,
thermostat-controlled cooling fans and heaters are used in all local
traffic signal cabinets.
Limited information is available regarding pre-and post-impact
to cabinet temperatures using artist wraps (such as vinyl anti-graffiti film) and/or other exterior treatments. As an alternative to an
aluminum or powder coated painted box (ie. cabinets), many local
agencies are applying artist wraps on existing cabinets or ordering
cabinets directly from the manufacturer with art displays. As part
of the TSB Art Project, an evaluation of the effects on the internal
cabinet temperature was studied to eliminate any maintenance
concerns regarding these various exterior surface treatments.
The Montana Department of Transportation (MDT) owns 82
traffic signals within the Great Falls District (Central and North
Montana). Most of MDT's traffic signal density is concentrated
A black traffic signal cabinet box in the City of Great Falls, MT, USA.
within the City (68 traffic signals) with 14 signals scattered
throughout the remaining part of the mostly rural District.
Whereas, the City owns and operates 23 traffic signals on City
streets. MDT contracts with the City's Public Works Department
on the maintenance of MDT-owned traffic signals within the City.
The cabinets as part of the TSB Art Project are on both city and
The TSB Art Project is now in its fifth year with nine of the 21
BID traffic signal cabinets wrapped with artist-vinyl. In 2012, MDT
maintenance recommended that the BID use artist wrap consisting
of a vandal proof heat-applied vinyl material in lieu of the artist
painted cabinet. This recommendation was made due to staff
concerns regarding the future "touch-up" and maintenance of the
artist's hand painted work.
In 2017, the BID approached the City and MDT for approval
to expand the TSB Art Project to two locations outside the BID.
During the initial process, maintenance personnel inquired
whether the artistic wrap (and various exterior treatments) would
have an impact on the internal temperature of the traffic signal
cabinet. There has been an industry-wide concern regarding
exterior treatments, with limited information on their effect.
Therefore, field measurements were conducted in a "living
laboratory" by the research team to see if there were any thermal
or insulating effects created from artist vinyl wrap (refer to Part IITemperature Evaluation with Varying Exterior Treatments).
w w w .i t e.or g
Apri l 2018