Project Title: Accounting for Large Trucks in the Design of Signs and Pavement Markings

Sponsor: Texas Department of Transportation

Principle Investigator: Melisa Finley

Research Staff:

TTI Project Number: 442692

Start Date: 9/1/01

End Date: 8/31/02

Abstract: In Texas, truck safety is increasing in priority due to the rising volume of truck traffic and the disproportionate percentage of crashes and fatalities involving trucks. One particular safety issue is the visibility of signing and pavement markings at night from a truck driver's perspective. Because large trucks are designed so that the drivers sit higher and federal codes mandate maximum headlamp heights so as to reduce oncoming glare, the eye/headlamp separation in large trucks is substantially greater than other types of vehicles. Thus, truck drivers are at a disadvantage when it comes to the amount of light returned from retroreflective devices such as signs and pavement markings. For example, sign brightness from a truck driver perspective is typically about 40 percent of a passenger car driver perspective. Currently, these issues are not considered in the design of signs and pavement markings. The purpose of this project is to identify sign and pavement marking mater ials that will provide adequate levels of luminance from the perspective of truck drivers while still meeting the requirements of drivers of lower vehicles.