RURAL ROADWAY CAPACITY AND CONGESTION - PHASE 1

Many of the currently recommended saturation flow values used to determine the congestion level on a roadway are based on data collected in urban area traffic streams; therefore the resulting computational values reflect urban conditions. This project summarized existing research to offer alternative saturation flow rates that reflect rural conditions. It investigated a number of topics pertaining to rural area capacity and congestion. The issues considered were related to freeways, signalized intersections, two-lane road passing and climbing lanes, and access design. The project reviewed existing passing/climbing lane simulation packages, and examined certain volume, headway, and passing behaviors. The practice of assuming less than five second headways constitute delay was tested, and found to be questionable under certain circumstances. The performances of three different arterial street access designs in a small city were compared. The accident rates and travel time delays varied according to the level of access control present. The arterial with the most access control had a considerably lower accident rate than the other two arterials.