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This study evaluated the safety effect of the flashing yellow arrow (FYA) treatment at signalized intersections. The major objective of this strategy is to reduce the frequency of left-turn (LT) crashes, especially those that involve a collision between left turns and vehicles traveling straight through from the opposite direction. The project team conducted an empirical Bayes before-after analysis of installations in Nevada, North Carolina, Oklahoma, and Oregon. The treatments were divided into seven categories depending on the phasing system in the before and after periods, number of roads where FYAs were implemented, and number of legs at each intersection. The first five categories involved permissive or protected-permissive phasing in the before period. Intersections in these five treatment categories experienced a reduction in the primary target crashes under consideration: LT crashes and left-turn-with-opposing-through (LTOT) crashes at the intersection level. The reduction ranged from 15 to 50 percent depending on the treatment category. Intersections in categories 6 and 7 had at least one protected LT phase in the before period, and after phasing had an FYA protected-permissive LT phase without time-of-day operation (category 6) and with time-of-day operation (category 7). Consistent with results from previous studies, these intersections experienced an increase in LT and LTOT crashes. The B/C ratios for categories 1-5 ranged from 56:1 to 144:1.
· 2025
This book is divided into two major parts: the Sales Section and the Distribution Section. The Sales Section focuses on optimizing the thinking patterns, working methods, and habits of sales personnel, exploring why there are significant differences in performance despite the same amount of time investment and busyness. The book emphasizes the importance of effective personal management and the transformation of thinking patterns. By adjusting working methods, learning to distinguish between important and urgent tasks, and focusing on key tasks, it aims to achieve a doubling of efficiency and performance.
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The Development of Crash Modification Factors program conducted the safety evaluation of cable median barriers in combination with rumble strips on the inside shoulder of divided roads for the Evaluation of Low Cost Safety Improvements Pooled Fund Study. This study evaluated safety effectiveness of cable median barriers in combination with rumble strips on the inside shoulders of divided roads. This strategy is intended to reduce the frequency of cross-median crashes, which tend to be very severe. Geometric, traffic, and crash data were obtained for divided roads in Illinois, Kentucky, and Missouri. To account for potential selection bias and regression-to-the-mean, an empirical Bayes before-after analysis was conducted using reference groups of untreated roads with characteristics similar to those of the treated sites. The analysis also controlled for changes in traffic volumes over time and time trends in crash counts unrelated to the treatment. In Illinois and Kentucky, cable median barriers were introduced many years after the inside shoulder rumble strips were installed; therefore, the evaluation determined the safety effect of implementing cable barriers along sections that already had rumble strips. Conversely, in Missouri, the inside shoulder rumble strips and cable barrier were implemented around the same time. Hence, the evaluation in Missouri determined the combined safety effect of inside shoulder rumble strips and cable barriers. The combined Illinois and Kentucky results indicate about a 27-percent increase in total crashes; a 24-percent decrease in fatal, incapacitating injury crashes; and a 48-percent decrease in head-on plus opposite-direction sideswipe crashes (used as a proxy for cross-median indicator plus head-on). the economic analysis for benefit-cost ratios shows that this strategy is cost beneficial.
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This study evaluated the safety effect of the flashing yellow arrow (FYA) treatment at signalized intersections. The major objective of this strategy is to reduce the frequency of left-turn (LT) crashes, especially those that involve a collision between and vehicles traveling straight through from the opposite direction.--Abstract.
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· 2018
The objective of the study was to evaluate the safety effects of two countermeasures with respect to vehicle–pedestrian crashes—the provision of protected or protected/permissive left-turn phasing and the provision of leading pedestrian intervals (LPIs)—using a before–after empirical Bayesian methodology. The study used data from North American cities that had installed one or both of the countermeasures of interest, including Chicago, IL; New York City, NY; Charlotte, NC; and Toronto, ON. This study showed that the provision of protected left-turn phasing reduced vehicle–vehicle injury crashes but did not produce statistically significant results for vehicle–pedestrian crashes overall. A disaggregate analysis of the effect of protected or protected/permissive left-turn phasing on vehicle–pedestrian crashes indicated that this strategy may be more beneficial when there are higher pedestrian and vehicle volumes, particularly above 5,500 pedestrians per day. At these high-volume locations, the left-turn phasing evaluation resulted in a potential benefit–cost (B/C) ratio range of 1:15.6::1:38.9. The evaluation of LPIs showed that the countermeasure reduced vehicle–pedestrian crashes. This evaluation produced a crash modification factor of 0.87 with a potential B/C ratio range of 1:207::1:517.