This research was tasked with exploring the second Strategic Highway Research Program (SHRP2) Naturalistic Driving Study (NDS) database for the potential to identify freeway entrance and exit ramps and teen drivers’ behaviour while travelling those ramps. This is in advance of a future task on National Cooperative Highway Research Project (NCHRP) Project 15-56, the objective of which is to review current practices for selecting design speed on freeway ramps and, if beneficial, recommend changes to those practices. The NCHRP project considers whether our current practices produce ramp design speeds that are consistent with the operating speeds that drivers actually choose, and if not, what changes should be made. The NCHRP 15-56 research team identified a selection of freeway ramps as possible study sites at which to collect data. That team also collected speed data and other variables on those ramps to compare actual speeds with the design elements of the ramp that influence the selection of a design speed. By exploring the features of the NDS dataset, researchers can a) consider a new tool for study site selection based on roadway characteristics and b) identify a potential new source of data that can either serve as a basis for analysis or serve as a comparison or validation of field data that researchers will collect through other methods. It will also provide a potential resource for research on other projects to explore driver behaviour, especially teen driver behaviour, and its relationships to roadway characteristics and other external influences. This report is organized with four chapters and an appendix, which are described as follows: Chapter 1 is this introductory chapter. Chapter 2 contains a discussion of the approach used by the research team to explore the datasets related to the SHRP2 NDS and identify variables of potential relevance. Chapter 3 describes the results of the research team’s query of the NDS dataset for events occurring on freeway ramps. Chapter 4 contains the researchers’ conclusions and recommendations on use of the NDS dataset for further research on freeway ramps. The appendix lists the variables contained in the SHRP2 database that were reviewed and explored by the research team. (Author/publisher)
Samenvatting