Estimation of critical gaps in two major streams

Different authors have presented capacity formulas for the case of more than one major lane when the lanes are not superposed. It has been shown that the allocation of the major flow on to the different lanes and different critical gaps for the major lanes have a substantial effect on the capacity for a minor lane. In this paper a maximum likelihood method for estimating the different critical gaps for the case of two major lanes is presented. The method can handle possible linear correlation between the critical gaps for the two major lanes. It is tested on simulated data and then applied on real data. It is then shown that the critical gaps differ between the two major lanes. The correlation coefficient was estimated for some of the subsets but for most of the subsets it was not possible to estimate.