Adverse weather degrades the capacities and operating speeds on roadways, resulting in congestion and productivity loss. Without a solid understanding of the mobility impacts of weather on traffic patterns, freeway operators do not have the estimates of speed and capacity reductions to predict and simulate the impacts of traffic management strategies. Nearly all traffic engineering guidance and...

Understanding the behavior of weaving flows and estimating the effects of time-variant traffic conditions on the capacity of weaving areas is of critical importance in developing effective operational strategies, which can achieve the maximum utilization of existing capacity for a given freeway system. The previous phase of this research identified and classified the major weaving areas in the ...

Existence of capacity drop phenomenon, as the difference between pre-queue and queue discharge flow rates, has been one of the controversial concepts of traffic engineering. Several researches have focused on capacity drop existence and also its estimation issues. This paper aims to estimate capacity drop based not only on a comparison between breakdown and queue discharge flow rates, but also ...

Although there are remarkable differences in drivers’ behavior as well as vehicles characteristics, road capacity estimationmethods in developing countries are same as developed ones. So, the discrepancy between the theoretical andpractical values of capacity is inevitable. Although, capacity estimation methods can be classified based on numerousparameters, in developing count...

The objective of this study is to determine whether ramp meters increase the capacity of active freeway bottlenecks, and if they do, how. The traffic flow characteristics at twenty-seven active bottlenecks in the Twin Cities have been studied for seven weeks without ramp metering and seven weeks with ramp metering. A series of hypotheses regarding the relationships between ramp metering and the...

Two neural network models, called clustering-RBFNN and clustering-BPNN models, are created for estimating the work zone capacity in a freeway work zone as a function of seventeen different factors through judicious integration of the subtractive clustering approach with the radial basis function (RBF) and the backpropagation (BP) neural network models. The clustering-RBFNN model has the attract...

The core methodology of the Highway Capacity Manual (HCM) 2010 for freeway analyses is based on Free-Flow Speed (FFS). Moreover, weaving segments are major elements of freeway facilities that form where two one-way traffic streams intersect by merging and diverging maneuvers. Hence, this study used three different methods to compute FFS of a ramp-weaving segment, and then employed the proposed ...