TTI Visibility Research

A New ASTM Standard for Retroreflected Luminance of Pavement Marking

f-ye@tti.servers — Mon, 23 Jul 2012 16:11:22 +0000

Dr. Paul Carlson, head of TTI Operations and Roadway Safety Division, speaks about a new ASTM International standard for Measuring the Coefficient of Retroreflected Luminance of Pavement Markings in a Standard Condition of Continuous Wetting. (Read more)

TRB Webinar: Practices and Examples to Manage Sign Retroreflectivity in Compliance with the MUTCD

f-ye@tti.servers — Mon, 19 Mar 2012 20:26:02 +0000

TRB will conduct a webinar on May 2, 2012, from 2:00 p.m.-3:30 p.m. ET that will explore the results of TRB’s National Cooperative Highway Research Program (NCHRP) Synthesis Report 431: Practices to Manage Traffic Signal Reflectivity, which will be released in April 2012. Dr. Paul Carlson, head of TTI Operations and Roadway Safety Division, will present for this webinar regarding MUTCD requirements related to minimum sign retroreflectivity standards and etc. (Read more and register here)

Dr.Carlson is Profiled in TR News!

f-ye@tti.servers — Fri, 09 Mar 2012 02:31:56 +0000

Dr.Paul J. Carlson, head of TTI Operations and Roadway Safety Division, is profiled in the January-February 2012 issue of TR News. The TR News is TRB’s bimonthly magazine, featuring timely articles on innovative and state-of-the-art research and practice in all modes of transportation. It is a great honor to be chosen for a profile piece. Congratulations, Paul! (Read more)

Road Angels-Traffic Technology International Article on pavement markings

Chris Sasser — Mon, 21 Mar 2011 14:34:29 +0000

Cast aside any aspersions you may have about the humble pavement marking. As Nick Bradley finds, these life-savers are worth every cent, while developments on the horizon are set to advance safety levels to a much higher plane. (Read more)

Raised question: TTI tests the durability of pavement markers

Chris Sasser — Thu, 10 Mar 2011 17:04:14 +0000

The worst of driving conditions calls for the best of roadway markers. With their reflective properties, retroreflective raised pavement markers (RRPMs) have guided many nervous drivers safely to their destination on rainy nights.

The durability and performance of RRPMs are critically important to departments of transportation nationwide. A few years ago, the Texas Department of Transportation (TxDOT) noticed an increased number of RRPM failures resulting from poor retention on pavements, physical damage and loss of retroreflectivity. In some cases, mass failures occurred when an entire section of RRPMs disappeared only weeks after installation. Read more

Guidelines for Nighttime Visibility of Overhead Guide Signs

Mark Coppock — Thu, 10 Mar 2011 16:23:30 +0000

A frequent dilemma facing highway agencies is deciding how to provide effective nighttime performance for overhead guide signs. While the Manual on Uniform Traffic Control Devices (MUTCD) provides minimum retroreflectivity standards for overhead guide signs, there are few guidelines that agencies can reference to decide how to provide sufficient nighttime performance of overhead guide signs in site-specific situations.

For instance, the common wisdom is that it is adequate to turn off overhead guide sign lighting in rural areas if highly reflective sheeting materials are used. However, there is little consensus about the use of lighting in suburban and urban areas where visual backgrounds and roadway geometries are more complex. Minimum sign retroreflectivity requirements are designed to provide conspicuity and legibility for all signs including overhead guide signs. In selected visual environments, such as urban areas with high visual complexity, higher levels of retroreflectivity or illumination or both may be needed to provide adequate conspicuity and legibility. (read more)