Vehicle Flow Characteristics on Acceleration Lanes

Abstract

The purpose of this study was to investigate flow characteristics on acceleration lanes. Four acceleration lanes in Israel, which were videotaped, provided the data. Three separate analyses were conducted: the locational distribution of merging places, acceleration characteristics of vehicles, and driver behavior during gap or lag acceptance. About 15% of the drivers tended to merge at a relatively sharp angle during the first quarter of the acceleration lane length, regardless of type. Also, light vehicles tended to merge much faster than did heavy vehicles. No great increases in speed were found to occur on the acceleration lanes. The difference in average speeds between vehicles on the through lane and vehicles at the far end of the acceleration lane was found to be somewhat higher than previously reported values. Findings lead to the conclusion that the majority of drivers do not seem to use the acceleration lane strictly for acceleration purposes; rather, the entire merging process is controlled by gap‐acceptance behavior. The importance of determining the proper location for a reference line for an analysis of rejected lags were found to decrease significantly with the placing of the reference line closer to the end of the acceleration lane. The necessity for adjusting the parameters of lag acceptance (since the driver population that rejects lags on acceleration lanes is composed of two subpopulations) is evaluated.