This research involved evaluating the simplified procedure for estimating passing demand. It was found that the equations in the simplified procedure for estimating passing demand between two streams has a critical flaw that occurs when the standard deviation of the speeds of the faster stream is low, causing the equations to estimate near zero passing demand when some demand would in fact exist. Additionally, probability distributions were fitted to actual speed data, and these distributions were used in a simple simulation model, to represent the speeds of vehicles in the two traffic streams. It was found that the logistic (not the Normal) distribution produced the best fit to the speed data. It was found that using these speed distributions in the simple simulation model, it is unnecessary to consider two separate traffic streams (for example cars and trucks) as required in the simplified procedure. (Author/publisher) For the covering entry of this conference, please see ITRD abstract no. E213656.
Samenvatting