Research on minor approach capacity model at unsignalized intersection under some specific conditions

This paper introduces one procedure for deducing the capacity model of minor approach at unsignalized intersection. Based on some assumptions and probability theory, the paper firstly analyzed different queuing morphological forms at the shared lane, and calculated each queue form´s probability when the queue included `n´ vehicles with `i´ left-turn vehicles and `j´ light vehicles. Secondly, it calculated the probabilities of main stream´s time-headway, which could permit `n´ queuing mixed vehicles passing by, when the main stream´s time-headway was accordance with the negative exponent distribution. Finally, the capacity model was deduced by calculating the mean value of vehicles passing by during one hour. Such procedure for getting the capacity model can be applied to any shared lanes of minor approach at unsignalized intersection, and It can deals with shared lanes for different geometric dimension vehicles and combined turns (e.g. though and left, though and right, etc.) simultaneously.