Predictor variables influencing merging speed change lane crash risk by interchange type in urban areas

• Published in: Transportation research interdisciplinary perspectives Vol. 10; p. 100375
• Main Authors: Tagar, Synthia, Pulugurtha, Srinivas S.
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01.06.2021; Elsevier
• Subjects: Crash; Merging; Multinomial Logistic Regression; Risk; Speed change Lane; Risk; Crash; Speed change Lane; Merging; Multinomial Logistic Regression
• DOI: 10.1016/j.trip.2021.100375
• ISSN: 2590-1982

•Merging speed change lane crash risk is higher at single-lane ramps compared to multi-lane ramps.•Ramp ADT at cloverleaf and freeway AADT at diamond interchanges influence merging speed change lane crash risk.•Speed diff. at cloverleaf and speed change lane length at diamond interchanges influence merging speed change lane crash risk.•Both upstream and downstream ramp distance influence merging speed change lane crash risk at cloverleaf interchanges.•Merging speed change lane crash risk is higher at four- and six-lane freeway sections at diamond interchanges. The objective of this research is to model and examine the influence of predictor variables on merging speed change lane crash risk by interchange type in urban areas. Data for selected merging speed change lanes in Charlotte, North Carolina, USA, for five-years, were collected and used in this research. Multinomial logistic regression models were developed to examine the risk of getting involved in a fatal or injury crash and property damage only (PDO) crash by interchange type. The findings indicate that merging speed change lanes at multi-lane ramps are safer than single-lane ramps (odds ratio > 50). The ramp average daily traffic (ADT) and the speed difference between the freeway and the ramp influence merging speed change lane crash risk at a cloverleaf interchange while the freeway annual average daily traffic (AADT) and the speed change lane length influence merging speed change lane crash risk at a diamond interchange (odds ratio > 1.4). The risk of getting involved in a fatal-injury crash in the merging speed change lane increases (odds ratio > 1.6) if an upstream or downstream ramp is too close to the subject cloverleaf interchange ramp or if a downstream ramp is too close to the subject diamond interchange ramp. Contrarily, the upstream ramp distance does not influence the merging speed change lane PDO crash risk at a cloverleaf or diamond interchange. It can be concluded that predictor variables influencing the merging speed change lane crash severity risk are different for cloverleaf, diamond, and other interchange types.