Evaluation of the Rain Effects on Gap Acceptance Behavior at Roundabouts by a Logit Model

Dongmin Lee,Eunhan Ka,Chungwon Lee,Sooncheon Hwang

doi:10.1155/2018/2726732

Dongmin Lee, Eunhan Ka + Show 2 more

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https://doi.org/10.1155/2018/2726732

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Abstract

A roundabout is generally known as an efficient, safe, and environmentally friendly intersection. Since 2010, the Korea government has taken the lead in constructing roundabouts as part of a special project. During that time, many ideas have been put forward to improve the safety, operation, and design of such roundabouts. In terms of improvements, it is particularly important to understand roundabout gap acceptance behavior. As such, we investigated gap acceptance behaviors at four roundabouts based on field observation during both good weather and rainy conditions. Based on the observed data, roundabout critical gaps were estimated, and a logit model for gap acceptance using various roundabout variables was developed to investigate gap acceptance maneuvering at roundabouts. A total of 2,421 data events for gap acceptance were collected from the field observation. Out of these events, 64.6% of drivers (1,564 drivers) accepted the given gaps and 35.4% of drivers (857 drivers) rejected them. The values for critical gaps were estimated using several different estimation methods and ranged from 3.3 to 4.7 seconds. The model was developed using four variables including gap size, type of circulating vehicle, traffic volume at the circulating lane, and weather conditions. The developed model shows that a longer gap results in a 3.669 times higher probability of entering roundabouts when the gap is sufficiently great for acceptance than when the gap is smaller. The effects of other variables, such as circulating vehicle types, circulating traffic volume, and weather conditions, are relatively lower than that of a gap size. Rain conditions influenced gap acceptance maneuvering around a roundabout. Drivers need about a 10 percent longer gap to accept entry into roundabouts during rainy conditions, and gap acceptance probabilities are 10 to 20 percent lower for the same given gap time during rainy conditions compared to good weather conditions.

Highlights

A roundabout is generally defined as a form of a circular intersection in which traffic travels counterclockwise around a central island and in which entering traffic must yield to circulating traffic [1]
Data for 1,681 vehicles were observed under good weather conditions, with 740 vehicles during rainy conditions
Gap acceptance behaviors at a roundabout were investigated based on field observations at four roundabouts during both good weather and rainy conditions

Summary

Introduction

A roundabout is generally defined as a form of a circular intersection in which traffic travels counterclockwise around a central island and in which entering traffic must yield to circulating traffic [1]. Roundabouts are generally considered an efficient intersection system to reduce intersection travel time, a safe intersection design to decrease the number of accidents and damage from accidents, and environmentally friendly. Many countries have incorporated roundabouts in their road designs, including Korea. Since 2010, roundabouts have been constructed in Korea as part of a special government-led project. There have been improvements in safety and efficiency benefits due to such construction. There have been many issues and ideas put forward to improve those roundabouts in terms of safety, operation, and Country Australia Frances Germany Netherlands United Kingdom United States Source: [1]

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