July 15, 2008
TTI Study: Effectiveness of Guide Signs with purple background
With the opening of the Westpark Tollway, the Harris County Toll Road Authority (HCTRA) began limited use of a new background color for tollway guide signs. These guide signs use a purple background with white letters. Purple is one of several colors in the Manual on Uniform Traffic Control Devices (MUTCD) that are "reserved" for a future use to be designated by the Federal Highway Adminstration (FHWA). HCTRA has recently been granted approval for a "Request to Experiment with Purple Guide Signs on Toll Roads". The Texas Transportation Institute (TTI) has completed this research proposal to support that experimentation.