Development of Analytic Method to Determine Weaving Patterns for Safety Analysis near Freeway Interchanges with Access Management Treatments
Dastgiri, Maryam Shirinzadeh
Dixon, Karen K.
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Urban arterials near freeway interchanges are vital elements of urban road infrastructures. They connect freeway network with high mobility and low access to urban network with lower mobility and higher access. This study investigates the operational safety of these elements and tries to find the relationship between geometric elements of roadway and the operational safety of urban arterials near interchanges. To measure the operational safety of urban arterials, the authors assumed lane changing as a risk factor and counted the number of lane changes over each study segment. Study segments were grouped to represent if they were located upstream to the freeway entrance or downstream to the freeway exit. The number of lane changes was used to define a new safety performance measure and was used as the dependent variable. Linear regression was used to construct statistical models. The results of this study showed that for downstream segments providing a median storage was the factor with the highest coefficient which means that median storages inversely impacted the safety performance of the roads. Adding a right running bay improved the safety performance of downstream segments, while having median openings and adding more driveways negatively impacted the safety performance of the study segments. For upstream segments right turning bays impaired the safety of the performance. Moreover, the number of driveways and proximity of the driveways were the next two factors with the highest negative impact on the safety performance of the roads.