الفهرس Only 14 pages are availabe for public view
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Abstract
Highway design practice in many countries in North America and europe is adopting the operating speed approach in design instead of the traditional design speed approach. Subsequently, over the past years considerable research was performed worldwide in this area to predict operating speed. Different approaches were used to measure the speeds and to model explanatory variables. Considerable research used spot speeds in predicting operating speeds, making the measurements subjected to bias or human error. This study presents three - dimensional and two - dimensional models developed to predict the 85th percentile operating speed and the 85th percentile deceleration/acceleration rates on horizontal curves for two - lane two-way rural highways. The operating speed was determined along the horizontal curves by using in - vehicle GPS equipment which allows continuous collecting and processing of speed data. GPS second by second speed data helped to obtain more accurate continuous speed profiles which enabled getting accurate deceleration and acceleration rates measurements