scholarly journals The Effects of Restricted Sight Distances on Drivers at Simulated Rural Intersections

2019 ◽  
Vol 63 (1) ◽  
pp. 2122-2123
Author(s):  
Jacob Achtemeier ◽  
Curtis M. Craig ◽  
Nichole L. Morris
Keyword(s):  
Time Pressure ◽  
Judgment Task ◽  
Vehicle Speed ◽  
Time To Collision ◽  
Sight Distance ◽  
Fatal Crashes ◽  
Oncoming Vehicle ◽  
Serious Injury ◽  
Motivating Factor ◽  
Design Factors

Short sight distances at rural intersections can result in reduced safety including drivers choosing smaller gaps between oncoming vehicles (Yan & Richards, 2010). Conversely, increased sight distances may result in improved driver confidence, but not safety as seen at rail crossings (Ward & Wilde, 1996). Thus, simply increasing sight distances may not result in linear gains in safety. Establishing appropriate lower and upper-visibility limits at rural intersections will minimize operational costs for clearing and grubbing labor and may reduce serious injury and fatal crashes by promoting safer crossing behavior around rural thru-STOP intersections. This driving simulation study will examine intersection visibility and other intersection design factors that influence driver behavior at rural thru-STOPs. Time to collision, or TTC, is a primary motivating factor on driver decisions to cross intersections. Drivers’ TTC perception is a function of oncoming vehicle speed, distance, and rate of retinal expansion (tau; Hancock & Manser, 1997). We hypothesize TTC factors may interact with confidence in intersection crossing judgments. Specifically, when people must quickly make judgments, their confidence must be estimated after the decision has been made, but if the time pressure is not high and the decision is not immediate, people’s judgments and their confidence in those judgments can both be considered prior to action. This can be problematic because people are normally overconfident in their judgments (Harvey, 1997). The present study comprised a crossing judgment block, and a mainline drive block. The experimental stimuli were validated by engineers with experience in rural intersections, who rated the simulated intersections as “significantly representative” to real-world intersections through an average rating score of 5.25 ( SD = 0.5) on a 7-pt scale. This was done to ensure that the study findings would be more likely to be applicable to world intersections. The goal of the study is to identify whether sight distance and other variables, including speed for the judgment task and vehicle proximity to the intersection for the mainline drive task, impact safety at rural intersections.

Passing Sight Distance and Overtaking Dilemma on Two-Lane Roads

1996 ◽  
Vol 1566 (1) ◽  
pp. 64-70 ◽  
Author(s):  
Chiu Liu ◽  
Robert Herman
Keyword(s):  
Traffic Control ◽  
General Framework ◽  
Previous Literature ◽  
Moving Frame ◽  
Sight Distance ◽  
Oncoming Vehicle ◽  
Analytic Expressions ◽  
Vehicle Acceleration ◽  
Acceleration And Deceleration ◽  
Control Devices

The overtaking dilemma involving two small vehicles was discussed by Herman and Lam in 1972. The formulation in a dynamical moving frame of the overtaken vehicle is extended by taking into account the pertinent variables for an overtaking scenario, such as vehicle acceleration and deceleration characteristics, roadway frictional characteristics, drivers' responses, and speeds of the overtaking vehicle and the oncoming vehicle in relation to the overtaken vehicle. A general framework dealing with overtaking is introduced, and analytic expressions for safe passing and aborting sight distances are derived for frictional roadway characteristics from the AASHTO guide. This formulation is further extended to other situations, namely, overtaking that involves a small and a long vehicle and overtaking that involves two long vehicles. Comparisons among our results, the AASHTO guide, the Manual on Uniform Traffic Control Devices on design for safe passing sight distances (PSD), and other related works are given for various overtaking situations. The overtaking scenario in which the vehicle overtaken is “fast” is addressed. Finally, the previous literature associated with the development of PSD is discussed.

scholarly journals Road Safety Impact of Increased Rural Highway Speed Limits in British Columbia, Canada

2018 ◽  
Vol 10 (10) ◽  
pp. 3555 ◽  
Author(s):  
Jeffrey Brubacher ◽  
Herbert Chan ◽  
Shannon Erdelyi ◽  
Gordon Lovegrove ◽  
Farhad Faghihi
Keyword(s):  
British Columbia ◽  
Road Safety ◽  
Systems Approach ◽  
Vehicle Speed ◽  
Linear Regression Models ◽  
Insurance Claims ◽  
Speed Limits ◽  
Fatal Crashes ◽  
The Impact ◽  
Road Segments

Control of vehicle speed is a central tenet of the safe systems approach to road safety. Most research shows that raising speed limits results in more injuries. Advocates of higher speed limits argue that this conclusion is based on older research, that traffic fatalities are decreasing despite higher speed limits, and that modern vehicles are able to safely travel at higher speeds. These arguments were used to justify raising speed limits on rural highways in British Columbia, Canada (July 2014). We used an interrupted time series approach to evaluate the impact of these speed limit increases on fatal crashes, auto-insurance claims, and ambulance dispatches for road trauma. Events were mapped to affected road segments (with increased speed limits) and to nearby road segments (within 5 km of an affected segment). Separate linear regression models were fitted for each outcome and road segment group. Models included gasoline sales to account for changes in vehicle travel. Our main findings were significant increases in (i) total insurance claims (43.0%; 95% Confidence Interval [CI] = 16.0–76.4%), (ii) injury claims (30.0%; 95% CI = 9.5–54.2%), and (iii) fatal crashes (118.0; 95% CI = 10.9–225.1%) on affected road segments. Nearby segments had a 25.7% increase in insurance claims (95% CI = 16.1–36.1%).

Influence of Advanced Placement of the In-Street Sign Gateway on Distance of Yielding from the Crosswalk

2018 ◽  
Vol 2672 (35) ◽  
pp. 13-20 ◽  
Author(s):  
Jonathan Hochmuth ◽  
Ron Van Houten
Keyword(s):  
Advanced Placement ◽  
Street Sign ◽  
Sight Distance ◽  
Data Points ◽  
Serious Injury ◽  
Reversal Design ◽  
Serious Injuries

A multiple-threat accident occurs when a pedestrian attempts to traverse a crosswalk on a multilane road, and the vehicle nearest to the pedestrian yields close to the crosswalk, obscuring the pedestrian’s view of the next lane, and the motorist’s view in the adjacent lane of the pedestrian. This set of circumstances may lead to pedestrians being struck at higher speeds by a vehicle in the adjacent oncoming lane, often resulting in serious injury or a fatality. The present study compared advanced placement of a gateway in-street sign configuration with a gateway deployed at the crosswalk, on two multilane roads. Data were collected using a reversal design, capturing alternating series of data points in each condition, and counterbalancing the order of those conditions. The advanced placement of the sign produced comparable levels of yielding to the crosswalk placement, but produced a large increase in the proportion of yielding 50 ft or further from the crosswalk. On multilane roads, increasing the distance at which vehicles yield from the crosswalk mitigates the sight distance issues that produce multiple-threat accidents, thereby reducing the likelihood of pedestrian fatalities or serious injuries. Advanced placement of the gateway configuration may also take the signs out of the turning radii of larger vehicles at a driveway or intersection, which may improve the longevity of the in-street signs.

Characterization of Opposite-Direction Road Departure Crashes in the United States

2013 ◽  
Vol 2377 (1) ◽  
pp. 14-20 ◽  
Author(s):  
Kristofer D. Kusano ◽  
Hampton C. Gabler
Keyword(s):  
Opposite Direction ◽  
The United States ◽  
Future Research ◽  
Sampling System ◽  
The Road ◽  
Vehicle To Vehicle ◽  
Fatal Crashes ◽  
Serious Injury ◽  
Serious Injuries

Opposite-direction crashes can be extremely severe because opposing vehicles often have high relative speeds. The objective of this study was to characterize the overall frequency of opposite-direction crashes as well as the frequency of crashes involving fatalities and serious injuries. The results of the study will guide future research and investment in infrastructure-based countermeasures to opposite-direction crashes, such as centerline rumble strips. The study used data from the National Automotive Sampling System (NASS) General Estimates System for 2010, the NASS Crashworthiness Data System for 2006 to 2010, and the Fatality Analysis Reporting System for 2010. The most common opposite-direction crash scenario was a driver departing the road driving over the centerline or the road edge to the left, which accounted for only 5% of nonjunction vehicle-to-vehicle crashes but 44% of serious injury and 49% of fatal crashes of the same type. Of the cross-over-to-left crashes, 72% of fatal crashes occurred on rural, undivided, two-lane roads and accounted for 1,659 fatal crashes in 2010. In cross-over-to-left crashes on rural two-lane roads, the driver was going straight or negotiating a curve in 88% to 94% of the crashes. The driver was overtaking another vehicle in only 2% of serious injury crashes and 6% of fatal crashes. Cross-over-to-left crashes on curves were to the outside of the curve more often than to the inside of the curve. This research suggests that countermeasures to opposite-direction crashes should focus on rural two-lane roads.

scholarly journals Analysis of passing sight distance using first-order reliability method

2021 ◽  
Author(s):  
Said Easa
Keyword(s):  
Safety Margin ◽  
Field Studies ◽  
Vehicle Speed ◽  
Second Moment ◽  
First Order ◽  
State Highway ◽  
Sight Distance ◽  
Design Variables ◽  
Reliability Method ◽  
First Order Second Moment

Current passing sight distance requirements for two lane highways by the American Association of State Highway and Transportation Officials are based on field studies conducted between 1938 and 1941 which use deterministic values for its design variables such as passing sight distance, speed of the passing vehicle, speed differential between the passed and passing vehicle etc. This report presents three methods to analyze reliability and serves as an extension to the revised model presented by Yasser Hassan, Said Easa and A.O.Abd El Halim whose model sought to improve older models by equally considering both observed passing behaviours of drivers and passing maneuvers that are consistent with two lane highways. Analysis of passing sight distance using first order second moment reliability method, advanced first order second moment and the ellipsoid approach to measure the probability of failure of the passing sight distance design, rely solely on the mean and variance (moments) of each randomly distributed variable in contrast to methods that rely only on deterministic values. Results show the advanced first order second moment and the ellipsoid approach provided more accurate results than first order second moment method which in turn provide a greater safety margin with the later also proving to be a much more robust and efficient method of performing a reliability

scholarly journals Fatal footsteps: Understanding the Safe System context behind New Zealand’s pedestrian road trauma

2021 ◽  
Vol 32 (1) ◽  
pp. 5-16
Author(s):  
Lily Hirsch ◽  
Hamish Mackie ◽  
Iain McAuley
Keyword(s):  
New Zealand ◽  
High Order ◽  
Vehicle Speed ◽  
Sociotechnical System ◽  
Infrastructure Design ◽  
Speed Management ◽  
System Factors ◽  
Serious Injury ◽  
Serious Injuries ◽  
System Context

In 2016 in New Zealand, pedestrians accounted for 7.6% (n=25) of all road fatalities and 6.6% (n=257) of serious injuries (Ministry of Transport, 2017). The aim of this research was to analyse a sample of pedestrian deaths and serious injury (DSI) cases to understand the contribution of Safe System gaps in serious harm outcomes. A sample of 100 pedestrian fatality and 200 serious injury crash reports from 2013-2017 were analysed to identify the contribution of the four Safe System pillars (roads and roadsides, vehicle, speed environment, user) in each crash case. The research identified common crash scenarios and highlighted the need for improvements in speed management, safer vehicles, safety campaigns, and infrastructure design. In addition, the research identified latent high-order sociotechnical system factors that obstruct the mechanisms to effectively address these Safe System issues and which ultimately perpetuate the occurrence of pedestrian DSIs.

scholarly journals Study on Traffic Conflict Prediction Model of Closed Lanes on the Outside of Expressway

Symmetry ◽  
2020 ◽  
Vol 12 (6) ◽  
pp. 926
Author(s):  
Huimin Ge ◽  
Mingyue Huang ◽  
Ying Lu ◽  
Yousen Yang
Keyword(s):  
Prediction Model ◽  
Traffic Accidents ◽  
Negative Binomial ◽  
Absolute Error ◽  
Vehicle Speed ◽  
Time To Collision ◽  
Traffic Characteristics ◽  
Traffic Conflicts ◽  
Traffic Conflict ◽  
Conflict Prediction

Due to the randomness and weak symmetry of traffic accidents occurring in the expressway maintenance operation area, it is difficult to use the number of traffic accidents to evaluate the safety of maintenance operation areas. In this paper, the traffic characteristics and traffic conflicts of the maintenance operation area with the lane closed on the outside of the two-way four-lane expressway are studied. By using the statistical method, the distribution of vehicle speed and time headway in different areas of the maintenance operation area are analyzed, and the queuing characteristics of vehicles in the upstream transition zone of the expressway are determined. Based on improved time to collision (TTC) model, the traffic conflict severity of expressway maintenance operation area is divided. The negative binomial distribution is used to establish a traffic conflict prediction model for the enclosed maintenance area of the outer lane of the expressway, and the validity of the traffic conflict prediction model is verified based on the average absolute error percentage (MAPE). The research results show that: when the 0 < TTC < 1.3 s, the traffic conflict is serious conflict; when 1.3 s < TTC, the traffic conflict is non-serious conflict. Furthermore, the traffic conflict prediction model has high accuracy, the MAPE of the warning area and the upstream transition area are 10.8% and 5.0%, respectively.

scholarly journals Roles of individual differences and traffic environment factors on children’s street-crossing behaviour in a VR environment

2019 ◽  
Vol 26 (5) ◽  
pp. 417-423 ◽  
Author(s):  
Huarong Wang ◽  
Zhan Gao ◽  
Ting Shen ◽  
Fei Li ◽  
Jie Xu ◽  
...  
Keyword(s):  
Risk Factors ◽  
Individual Differences ◽  
Sensation Seeking ◽  
Vehicle Speed ◽  
Environment Factors ◽  
Traffic Environment ◽  
Serious Injury ◽  
Children’S Behaviour ◽  
Pedestrian Crossing ◽  
Sensation Seeking Scale

ObjectivePedestrian injuries are among the most common cause of death and serious injury to children. A range of risk factors, including individual differences and traffic environment factors, has been investigated as predictors of children’s pedestrian behaviours. There is little evidence examining how risk factors might interact with each other to influence children’s risk, however. The present study examined the independent and joint influences of individual differences (sex and sensation seeking) and traffic environment factors (vehicle speeds and inter-vehicle distances) on children’s pedestrian safety.MethodsA total of 300 children aged 10–13 years were recruited to complete a sensation-seeking scale, and 120 of those were selected for further evaluation based on having high or low sensation-seeking scores in each gender, with 30 children in each group. Children’s pedestrian crossing behaviours were evaluated in a virtual reality traffic environment.ResultsChildren low in sensation seeking missed more opportunities to cross and had longer start gaps to enter the roadway compared with those high in sensation seeking, and these effects were more substantial when vehicles were spread further apart but travelling slowly. Interaction effects between inter-vehicle distance and vehicle speed were also detected, with children engaging in riskier crossings when the car was moving more quickly and the vehicles were spread further than when the vehicles were moving quickly but were closer together. No sex differences or interactions emerged.ConclusionBoth sensation seeking and traffic environment factors impact children’s behaviour in traffic, and there are interactions between traffic speeds and inter-vehicle distances that impact crossing behaviour.

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