Retroreflectivity of existing signs in Pennsylvania.

Final report.PDFTech ReportFHWA-PA-2012-003-E01041-WO9E01041, Work Order 9Traffic signsReflective signsRetroreflectivityService lifePennsylvaniaPennsylvania. Dept. of TransportationClevenger, KyleColello, KarenQuirus, JeannetteMcCormick Taylor (Firm)Pennsylvania. Dept. of Transportation. Bureau of Maintenance and OperationsUnited States. Federal Highway AdministrationNTL-OPERATIONS AND TRAFFIC CONTROLS-Traffic Control DevicesNTL-SAFETY AND SECURITY-Highway SafetyUS Transportation CollectionThe Pennsylvania Department of Transportation (PennDOT) Bureau of Highway Safety and Traffic Engineering initiated thisresearch effort in response to the release of the new 2009 Manual on Uniform Traffic Control Devices (MUTCD) which mandatesthat all states shall have a sign maintenance method designed to maintain traffic sign retroreflectivity at or above the establishedminimum levels in place by January 2012. The goal of this research effort was to collect and analyze sign retroreflectivitymeasurements on a subset of PennDOT owned and maintained signs throughout the Commonwealth of Pennsylvania in order tobetter understand the potential service life of signs with regard to nighttime visibility in Pennsylvania. As PennDOT implements itssign management system, with respect to compliance with the minimum retroreflectivity levels, the findings of this research willassist PennDOT in better determining when signs may need replaced. Retroreflectivity levels were measured on a sample of 1,000traffic signs using a DELTA Light and Optics RetroSign 4500 retroreflectometer. In order to obtain regional variety, an equalportion of signs (one third in each county) were measured in Lackawanna, Lehigh and Lancaster counties to represent thenorthern, central and southern tiers of the state. The number of yellow warning signs, white regulatory signs, green directionalsigns and red Stop, Yield, Do Not Enter and Wrong Way signs to be measured was determined using the proportion of each signcolor\ue2\u20ac\u2122s overall population in the state. PennDOT\ue2\u20ac\u2122s current standard specifications for reflective sheeting require the use of Type IIIor Type IV sheeting for post-mounted sign installations and the sign sheeting manufacturer warranties are typically 10 years;therefore the data collection efforts were limited to Type III signs aged 10 years or older. The study recommends an expected signlife of 15 years for yellow, white, red and green signs in Pennsylvania