This paper presents speed/travel time estimation techniques developed through the NCHRP 7-13 study "Quantifying Congestion" using empirical field data. The estimation procedures use readily available roadway inventory and traffic volume data. A methodology developed for freeways uses average daily traffic (ADT) volumes per lane and access point frequency as a simple predictor of speeds. The queueing effects of bottlenecks can also be incorporated into the predictive model to account for sections upstream of geometric bottlenecks or congestion points. An estimation procedure for arterial streets relies on ADT per lane and signal density to estimate speeds. The paper also describes how congestion estimates can be combined with data collection to quantify congestion for future conditions. (A)
Samenvatting