| dc.description.abstract | This thesis research investigated the predictive performance of pavement
marking retroreflectivity measured under various conditions of continuous wetting. The
researcher compared nighttime detection distance of pavement markings in simulated
rain conditions and the retroreflectivity of the same pavement markings in several
continuous wetting conditions. Correlation analyses quantified the predictive
performance of the resulting retroreflectivity values from the continuous wetting
conditions.
The researcher measured the retroreflectivity of 18 pavement marking samples
under 14 different conditions. The American Society for Testing and Materials (ASTM)
has three standards for measuring the retroreflectivity of pavement markings under:
dry (E-1710), recovery (E-2177), and continuous wetting conditions (E-2176). Using
three ASTM standard conditions resulted in three sets of retroreflectivity data, and
variations of the continuous wetting standard produced an additional 11 sets of
continuous wetting condition data.
The researcher also incorporated detection distance values measured for the
same 18 pavement marking samples under three different simulated rainfall conditions at night. The three conditions included: high (0.87 in/hr), medium (0.52 in/hr), and low
(0.28 in/hr) flow rates, these rates were to simulate typical rainfall rates in the state of
Texas.
The correlation analyses measures the linear relationship as well as the
logarithmic relationship between the detection distance and the retroreflectivity of the
pavement markings. A pavement markings' retroreflectivity is typically used as a
detection distance performance indicator, therefore a high degree of correlation between
retroreflectivity and detection distance would be desired. A high degree of correlation
would indicate that a measured retroreflectivity value of a pavement marking would
provide a good indication of the expected detection distance.
The researcher conducted analyses for several subgroups of the pavement
markings based on the markings type or characteristics. Dry, recovery, and all the
continuous wetting retroreflectivity data were correlated to the detection distances.
Correlation values found during this thesis research did not show a high degree of
correlation for most of the subgroups analyzed. This indicates that measured
retroreflectivity would not provide very good predictive performance of the pavement
markings detection distance in rainy conditions. | en |
