Evaluation of Roundabout-Related Single-Vehicle Crashes

2017 ◽  
Vol 2637 (1) ◽  
pp. 17-26 ◽  
Author(s):  
Beau Burdett ◽  
Andrea R. Bill ◽  
David A. Noyce
Keyword(s):  
Negative Binomial ◽  
Vehicle Crashes ◽  
Impaired Driving ◽  
Crash Data ◽  
Road Crashes ◽  
Run Off ◽  
Traffic Volumes ◽  
Single Vehicle ◽  
Total Proportion ◽  
Crash Types

Roundabouts reduce fatal and injury crashes at intersections when converted from other intersection control types. In Wisconsin, roundabouts have been linked to a 38% decrease in fatal and injury crashes. Part of this reduction can be attributed to crash types that result in the mitigation of more serious injuries. However, the reduction comes at a cost because other crash types, such as single-vehicle collisions, may increase. Six years of crash data on 53 roundabouts in Wisconsin were examined for crash causes and geometric characteristics that affected single-vehicle crashes. Weather and impaired driving, particularly by younger drivers, were primary causes for more than half of all single-vehicle crashes at the study roundabouts. Younger drivers (18 to 24 years of age) were involved in a significantly higher proportion of single-vehicle crashes than the total proportion of licensed drivers in that age group. Younger drivers were involved in approximately one-third of all crashes that involved impaired driving and in two-thirds of all speed-related single-vehicle crashes. A negative binomial model was constructed to estimate run-off-road crashes at approaches. It was found that roundabouts with higher approach speeds and higher traffic volumes experienced more run-off-road crashes. Landscaped central islands experienced significantly lower frequencies of run-off-road crashes.

Effects of Ramp Spacing on Freeway Mainline Crashes

2011 ◽  
Vol 97-98 ◽  
pp. 95-99
Author(s):  
Yong Qing Guo
Keyword(s):  
Regression Models ◽  
Negative Binomial ◽  
Negative Binomial Regression ◽  
Model Estimation ◽  
Vehicle Crashes ◽  
Crash Data ◽  
Binomial Regression ◽  
Single Vehicle ◽  
Exit Ramp

This research applies Negative Binomial regression models to investigate safety effects of ramp spacing. Data for model estimation was collected in 112 freeway segments where each entrance ramp is followed by an exit ramp. Three years (2005-2007) of freeway crash data were examined by the NB model in this study. The modeling results suggest that the frequencies of total crashes, fatal-plus-injury crashes, single-vehicle crashes and multiple-vehicle crashes increase as ramp spacing decreases, and the frequencies of total crashes and multiple-vehicle crashes increase at significant rates. The modeling result has been geared into the development of accident modification factors (AMFs) for ramp spacing that can be used safety prediction of freeways.

scholarly journals Motor Scooters and Mopeds

2008 ◽  
Vol 2074 (1) ◽  
pp. 69-76 ◽  
Author(s):  
Narelle Haworth ◽  
Angela Nielson
Keyword(s):  
Medical Treatment ◽  
The State ◽  
Crash Severity ◽  
Loss Of Control ◽  
Vehicle Crashes ◽  
Low Speed ◽  
Registration Data ◽  
Single Vehicle ◽  
Crash Types ◽  
Motorcycle Crashes

Little is known about the crash involvement of scooters and mopeds and whether they are safer than other motorcycles. Difficulties in defining motor scooters and mopeds and identifying them in crash and other databases have hindered research. This paper reviews recent research and analyzes the nature and extent of moped and motorcycle crashes in the State of Queensland, Australia. Analyses of merged crash and registration data found that the number of moped crashes increased from 25 in 2001 to 97 in 2005. Most crashes resulted in hospitalization (43%) or medical treatment (38%) and occurred between 6 a.m. and 6 p.m. on weekdays in low-speed areas. Overall, 50.8% of crashes occurred at intersections and 32.3% were single-vehicle crashes. The most common crash types were collisions between vehicles traveling in the same direction (24.8%), loss of control on a straight road (23.1%), and collisions between the moped and another vehicle on an adjacent approach to an intersection (18.2%). The ratio of motorcycle to moped crashes was about 19:1, but moped crashes increased at a greater rate during 2001–2005 (260% versus 71%). The distributions of crash severity were similar. Moped crashes more often involved loss of control on a straight road (23.1% versus 12.7%), while motorcycle crashes more often involved loss of control on a curve (13.6% versus 5.0%). Moped riders in crashes were much more likely than motorcycle riders to be female (37.9% versus 7.2%) and younger and hold an interstate (10.8% versus 1.3%) or overseas (7.8% versus 0.7%) license. The interpretation of these data and their implications for licensing and other countermeasures are discussed.

Examining the factors affecting the severity of run-off-road crashes in Abu Dhabi

2016 ◽  
Vol 43 (2) ◽  
pp. 132-138 ◽  
Author(s):  
Mohamed Shawky ◽  
Hany M. Hassan ◽  
Atef M. Garib ◽  
Hussain A. Al-Harthei
Keyword(s):  
Traffic Safety ◽  
Surface Condition ◽  
Probit Model ◽  
Abu Dhabi ◽  
Factors Affecting ◽  
Environment Factors ◽  
Crash Data ◽  
Road Crashes ◽  
Run Off ◽  
Road Type

Recently, the severity of injuries resulting from traffic crashes has been extensively investigated in numerous studies. However, the number of studies that addressed the severity of the run-off-road (ROR) crashes is relatively low. In the Emirate of Abu Dhabi (AD), approximately 22% of the total serious crashes and fatalities that occurred from 2007 to 2013 were ROR crashes. Despite these facts and the uniqueness of the composition of licensed drivers in AD (approximately 87% of them are non-Emiratis), the factors affecting the occurrence and severity of ROR crashes in AD have not been explicitly addressed in any prior studies. Therefore, this study aims to investigate the characteristics of at-fault drivers involved in ROR crashes in AD, the nature and main causes of those crashes. In this regard, conditional distribution and two-way contingency tables were developed. In addition, this study aims to identify and quantify the factors affecting the severity of ROR crashes such as driver, road, vehicle and environment factors. To achieve this goal, ordered probit model approach was employed. Crash data for a total of 3819 ROR crashes that occurred in AD were employed in the analysis. The results indicated that driver factors (carelessness, speeding, and nationality), vehicle characteristics (vehicle type), and road and environment factors (road type, crash location and road surface condition) were the significant factors influencing the severity of ROR crashes in AD. Countermeasures to improve traffic safety and reduce numbers and severity of ROR crashes in AD were discussed.

Safety Evaluation of Alternative Audible Lane Departure Warning Treatments in Reducing Traffic Crashes: An Empirical Bayes Observational Before–After Study

2018 ◽  
Vol 2672 (21) ◽  
pp. 30-40 ◽  
Author(s):  
Lingtao Wu ◽  
Srinivas R. Geedipally ◽  
Adam M. Pike
Keyword(s):  
Empirical Bayes ◽  
Safety Evaluation ◽  
Highway Safety ◽  
Warning Systems ◽  
Lane Departure Warning ◽  
Crash Data ◽  
Pavement Markings ◽  
Lane Departure ◽  
Run Off ◽  
Single Vehicle

Roadway departure crashes are a major contributor to traffic fatalities and injury. Rumble strips have been shown to be an effective countermeasure in reducing roadway departure crashes. However, some roadway situations, for instance, inadequate shoulder width or roadway surface depth, have limited the application of conventional milled or rolled in rumble strips. Alternative audible lane departure warning systems, including profile (audible) pavement markings and preformed rumble bars, are increasingly used to overcome the limitations that exist with the milled rumble strips. So far, the safety effectiveness of these alternative audible lane departure warning systems has not been extensively assessed. The main purpose of this paper is to examine the safety effect of installing profile pavement markings and preformed rumble bars. Specifically, this study developed crash modification factors for these treatments that quantify the effectiveness in reducing single-vehicle-run-off-road (SVROR) and opposite-direction (OD) crashes. Traffic, roadway, and crash data at the treated sites on 189 miles of rural two-lane highways in Texas were analyzed using an empirical Bayes (EB) before–after analysis method. Safety performance functions from the Highway Safety Manual and Texas Highway Safety Design Workbook were used in the EB analysis. The results revealed a 21.3% reduction in all SVROR and OD crashes, and 32.5% to 39.9% reduction in fatal and injury SVROR and OD crashes after installing profile pavement marking and preformed rumble bars.

scholarly journals Use of single vehicle collisions to model fatigue-related crashes on rural two-lane highways

2021 ◽  
Author(s):  
Xu Lin
Keyword(s):  
Circadian Rhythm ◽  
Traffic Safety ◽  
Safety Information ◽  
Rural Highways ◽  
Formidable Challenge ◽  
Average Curvature ◽  
Run Off ◽  
Traffic Volumes ◽  
Single Vehicle ◽  
Design Factors

Fatigue-related crashes are believed to be more common on rural highways than on urban roads and on two-lane roads rather than on other rural road types. Thus an understanding of how design factors affect fatigue-related crashes on rural to-lane roads is vital. The problem is that fatigue is rarely reported as a cause of crashes, since is is rarely suspected by the police as a possible cause and since potential liability may motive the drivers not to reveal the real causes of the crash. Thus, getting a handle on these crashes thorough modeling is a formidable challenge. Fortunately, there is research to suggest that single-vehicle run-off-road crashes, particularly those during periods of low circadian rhythm, can be used as a reasonable surrogate in modeling fatigue--related crashes. The paper is based on research to examine how fatigue-related crashes rural on two-lane roads, as represented by single vehicle crashes, are affected by various engineering design factors. This study's goal is to explore the effects of fatigue on driving on rural two-lane roads in North America, and to consider how we can work towards mitigating the effects of fatigue on traffic safety. For this investigation, generalized linear and logistic regression modelling were used on US Highway Safety Information System (HSIS) data from Ohio. Models were developed separately and combined for periods of high and low circadian rhythm and for single-vehicle run-off-road and other crashes. The results show, for example, the after controlling for traffic volumes, increases in speed limit, average curvature and average gradient and decreases in surface width and average shoulder width were found to be associated with increased fatigue related crashes. Important differences were found in the effects of factors for period of low and high circadian rhythm.

scholarly journals Urban Road Crashes and Weather Conditions: Untangling the Effects

2019 ◽  
Vol 11 (11) ◽  
pp. 3176 ◽  
Author(s):  
António Lobo ◽  
Sara Ferreira ◽  
Isabel Iglesias ◽  
António Couto
Keyword(s):  
Negative Binomial ◽  
Weather Conditions ◽  
Crash Risk ◽  
Traffic Crash ◽  
Road Crashes ◽  
Road Users ◽  
Poisson Models ◽  
Adverse Weather ◽  
Single Vehicle ◽  
The Impact

Most previous studies show that inclement weather increases the risk of road users being involved in a traffic crash. However, some authors have demonstrated a little or even an opposite effect, observed both on crash frequency and severity. In urban roads, where a greater number of conflict points and heavier traffic represent a higher exposure to risk, the potential increase of crash risk caused by adverse weather deserves a special attention. This study investigates the impact of meteorological conditions on the frequency of road crashes in urban environment, using the city of Porto, Portugal as a case study. The weather effects were analyzed for different types of crashes: single-vehicle, multi-vehicle, property-damage-only, and injury crashes. The methodology is based on negative binomial and Poisson models with random parameters, considering the influence of daily precipitation and mean temperature, as well as the lagged effects of the precipitation accumulated during the previous month. The results show that rainy days are more prone to the occurrence of road crashes, although the past precipitation may attenuate such effect. Temperatures below 10 °C are associated with higher crash frequencies, complying with the impacts of precipitation in the context of the Portuguese climate characteristics.

scholarly journals Evaluating Safety of Type-A Weaving Sections Using Geometric and Traffic Operational Factors

2020 ◽  
Vol 9 (6) ◽  
pp. 21
Author(s):  
Venkata Mallipaddi ◽  
Michael Anderson
Keyword(s):  
Traffic Congestion ◽  
Urban Areas ◽  
Negative Binomial ◽  
Type A ◽  
Warning Signs ◽  
Crash Data ◽  
Positive Effects ◽  
Single Vehicle ◽  
Crash Modification Factors ◽  
Operational Factors

The efficiency and safety of type-A freeway weaving sections in urban areas are constrained by recurrent bottlenecks. Limited space in freeway weaving sections cause traffic congestion and crashes during peak-hours. Various factors, including length of weaving section, continuity of lanes, and number of lanes will have significant effects on the level of service and safety performance of the weaving sections. Eight years (2010-2017) of crash data in the type-A weaving sections was used in this analysis. The objective of this study aims to evaluate geometric design factors and operational factors on total crashes and each of the four crash types: rear-end, sideswipe, angle, and single-vehicle in type-A weaving sections using traditional negative binomial approach and develop crash modification factors (CMFs) to improve safety in the type-A weaving section. The results revealed that on-ramp traffic per hour, off-ramp traffic per hour, non-weaving traffic per hour, weaving ratio, length of the weaving section, direction of the freeway, width of inside shoulder, and width of outside shoulder were influencing crashes in type-A weaving sections. Furthermore, the estimated crash modification factors (CMFs) result revealed that total crashes gradually decrease as inside shoulder width increases. This implies that widening inside shoulder width have positive effects on weaving section safety. In addition, ramp metering, and advisory warning signs could improve safety in type-A weaving sections.

scholarly journals Assessment of traffic safety at median openings using surrogate safety measures: a case study in India

2020 ◽  
Vol 80 (ET.2020) ◽  
pp. 1-12
Author(s):  
Malaya Mohanty
Keyword(s):  
Developing Countries ◽  
Traffic Safety ◽  
Transportation Engineering ◽  
Crash Data ◽  
Road Crashes ◽  
The Road ◽  
Sight Distance ◽  
Traffic Volumes ◽  
Road Crash ◽  
Stopping Sight Distance

Traffic safety is an integral part of transportation engineering. In developing countries, its importance is even more. Additionally, at uncontrolled median openings, the severity of road crashes increase many fold. Conventionally, road crash data were used to analyse safety. However, in developing countries, the accuracy of this data is highly questionable. Therefore, in this study, a new technique in addition to post encroachment time (PET), which is a surrogate safety measure is used to predict the severity of probable road crashes at median openings. After the extraction of PET values from field data, they have been compared with the minimum braking times obtained from calculation of minimum stopping sight distance. The comparison shows that while the number of road crashes may be less at lower traffic volume levels, however the severity of those crashes is much higher as compared to the road crashes occurring at high traffic volumes.

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