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There have been limited efforts to investigate the potential of using detailed trajectory data obtained from connected vehicles and/or other sensors in deriving metrics for use in real-time assessment of traffic safety. This study investigated the use of disturbance metrics for this purpose. The disturbance metrics considered were the number of oscillations (NoO) and a measure of disturbance durations in terms of the time exposed time-to-collision index (TETIndex). The time exposed time-to-collision (TET) has been widely used as a safety surrogate measure, but there is no study on the identification of its thresholds to justify activating plans to mitigate unsafe conditions in real-time operations. This study found a TETIndex of 0.03 and NoO of 10% can be used to recognise unsafe conditions in the case study of this research. Since estimation of the TETIndex requires the location and speed of both leading and following vehicles and therefore cannot be measured accurately with low sample sizes of vehicle trajectories, a regression model was derived to estimate the TETIndex based on speed parameters. It was also found that the investigated disturbance metrics and associated models and thresholds are significantly related to crash occurrence and can thus be used in the activation of transportation management strategies to reduce the probability of unsafe traffic and ease traffic disturbances that have an adverse impact on traffic safety.

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Tramadol is a potent analgesic drug which interacts with mu-opioid and has low effect on other opioid receptors. Unlike other opioids, it has no clinically significant effect on respiratory or cardiovascular parameters. Alakaline phosphatase is a hydrolase enzyme that prefers alkaline condition and removes phosphate group from different substrates. In this study, the interaction between tramadol and calf liver alkaline phosphatase was investigated. The results showed that tramadol can bind to alakaline phosphatase and inhibit the enzyme in an un-competitive manner. Ki and IC50 values of tramadol were determined as about 91 and 92 μM, respectively. After enzyme purification, structural changes on alakaline phosphatase-drug interaction were studied by circular dichroism and fluorescence measurement. These data revealed the alteration in the content of secondary structures and also conformational changes in enzyme occurred when the drug bound to enzyme-substrate complex.