Study of Intersection Accidents by Maneuver Type

2002 ◽  
Vol 1784 (1) ◽  
pp. 43-50 ◽  
Author(s):  
Sudeshna Mitra ◽  
Hoong Chor Chin ◽  
Mohammed Abdul Quddus
Keyword(s):  
Traffic Control ◽  
Traffic Accidents ◽  
Signalized Intersections ◽  
Probability Models ◽  
Left Turn ◽  
Factors Affecting ◽  
Adaptive Signal Control ◽  
Road Geometry ◽  
Accident Data ◽  
Adaptive Signal

Studies dealing with the effect of road geometry on accidents by vehicle maneuvers have been reported, mostly for western countries and a few for Asia. However, no such studies have been reported for Singapore. Traffic accidents arising from head-to-side and head-to-rear maneuvers at four-legged signalized intersections in Singapore were investigated. Based on accident data at intersections in the southwestern part of Singapore from 1992 to 1999, the factors affecting such accidents were explored using zero-altered probability models. Specific roadway geometries as well as traffic control and regulatory factors that influence the two categories of accidents were identified. It was found that head-to-side accidents tend to decrease if there is an adjacent intersection within 200 m and if bus stops along the approach are provided with bays. On the other hand, longer sight distances and the presence of a pedestrian refuge tend to increase this type of accident. Higher speed limits were found to reduce the instances of zero head-to-side accidents. It was also found that head-to-rear accidents decrease when the intersections are under adaptive signal control but increase when surveillance cameras are present. There is also some evidence to suggest that the presence of an uncontrolled left-turn channel, the existence of medians wider than 2 m, higher approach volumes, and more phases per cycle all contribute to higher instances of accidents by both maneuver types.

Real-Time Detector-Free Adaptive Signal Control with Low Penetration of Connected Vehicles

2018 ◽  
Vol 2672 (18) ◽  
pp. 35-44 ◽  
Author(s):  
Yiheng Feng ◽  
Jianfeng Zheng ◽  
Henry X. Liu
Keyword(s):  
Real Time ◽  
Traffic Control ◽  
Penetration Rate ◽  
Traffic Volume ◽  
Signal Control ◽  
Connected Vehicle ◽  
Estimation Model ◽  
Loop Detectors ◽  
Adaptive Signal Control ◽  
Adaptive Signal

Most of the existing connected vehicle (CV)-based traffic control models require a critical penetration rate. If the critical penetration rate cannot be reached, then data from traditional sources (e.g., loop detectors) need to be added to improve the performance. However, it can be expected that over the next 10 years or longer, the CV penetration will remain at a low level. This paper presents a real-time detector-free adaptive signal control with low penetration of CVs ([Formula: see text]10%). A probabilistic delay estimation model is proposed, which only requires a few critical CV trajectories. An adaptive signal control algorithm based on dynamic programming is implemented utilizing estimated delay to calculate the performance function. If no CV is observed during one signal cycle, historical traffic volume is used to generate signal timing plans. The proposed model is evaluated at a real-world intersection in VISSIM with different demand levels and CV penetration rates. Results show that the new model outperforms well-tuned actuated control regarding delay reduction, in all scenarios under only 10% penetrate rate. The results also suggest that the accuracy of historical traffic volume plays an important role in the performance of the algorithm.

scholarly journals Comparison of Crash Severity Risk Factors at Signalized and Stop-Controlled Intersections in Urban and Rural Areas in Alabama

2018 ◽  
Vol 7 (5) ◽  
pp. 50
Author(s):  
Sumalatha Kesavareddy ◽  
Kirolos Haleem ◽  
Mehrnaz Doustmohammadi ◽  
Michael Anderson
Keyword(s):  
Traffic Control ◽  
Rural Areas ◽  
Signalized Intersections ◽  
Crash Severity ◽  
Factors Affecting ◽  
Side Impacts ◽  
Binary Logit ◽  
Urban And Rural Areas ◽  
New Variables ◽  
Significant Factors

Understanding the factors that affect crash severity at intersections is essential to develop strategies to alleviate safety deficiencies. This paper identifies and compares the significant factors affecting crash severity at signalized and stop-controlled intersections in urban and rural areas in Alabama using recent five-year crashes. A random forest model was used to rank variable significance and a binary logit model was applied to identify the significant factors at both intersection types in urban and rural areas. Four separate models (urban signalized, urban stop-controlled, rural signalized, and rural stop-controlled) were developed. New variables that were not previously explored were used in this study, such as the roadway type (one-way vs. two-way) and traffic control functioning (yes or no). It was found that one-way roadways were associated with a reduction in crash severity at urban signalized intersections. In all four models, rear-end crashes showed lesser severity than side impacts. Head-on crashes, higher speed limits, and curved sections showed higher severity in urban signalized and stop-controlled intersections. In rural stop-controlled intersections, right-turning maneuvers had a severity reduction. Female drivers showed 15% and 45% higher severity likelihood (compared to males) at urban and rural signalized intersections, respectively. Strategies to alleviate crash severity are proposed.

scholarly journals Safety evaluation of left-turn priority phasing at Toronto intersections

2021 ◽  
Author(s):  
Anwarul Haq Dogar
Keyword(s):  
Traffic Safety ◽  
Traffic Accidents ◽  
Safety Evaluation ◽  
Vital Role ◽  
Signalized Intersections ◽  
Side Impact ◽  
Empirical Bayesian ◽  
Left Turn ◽  
Safety Performance Functions ◽  
The City

Traffic accidents cause a huge loss to the society. According to statistics, 50% of all accidents occur at urban intersections and 47% of these are due to left-turn collisions. Countermeasure Implementation at these locations therefore can play a vital role in the improvement of traffic safety. This study illustrates a methodology for evaluation of urban 4-legged signalized intersections treated with left-turn priority phasing. The methodology is applied to three important collisions types: those due to left-turn collisions; those due to left-turn side impact collisions; and all impact types combined collisions. Data used in this analysis were obtained from the City of Toronto. Safety Performance Functions for left-turn and all impact types combined collisions which were developed by the City of Toronto, were calibrated and used in an empirical Bayesian methodology that was employed to estimate the expected frequency of accidents occurring at each intersection in order to evaluate the effectiveness of left-turn priority phasing in reducing this frequency. The results revealed that left-turn priority phasing can be an effective treatment for addressing and reducing the number of collision at signalized intersections. Flashing advance green phasing is more effective in improving safety for two of three types; all left-turn and all impact types combined collisions. Left-turn green arrow (protected/permissive) phasing is more effective for left-turn side impact collisions. By implementing this type of treatment, the number of crashes and the associated monetary loss to society could be significantly reduced.

scholarly journals Safety evaluation of left-turn priority phasing at Toronto intersections

2021 ◽  
Author(s):  
Anwarul Haq Dogar
Keyword(s):  
Traffic Safety ◽  
Traffic Accidents ◽  
Safety Evaluation ◽  
Vital Role ◽  
Signalized Intersections ◽  
Side Impact ◽  
Empirical Bayesian ◽  
Left Turn ◽  
Safety Performance Functions ◽  
The City

Traffic accidents cause a huge loss to the society. According to statistics, 50% of all accidents occur at urban intersections and 47% of these are due to left-turn collisions. Countermeasure Implementation at these locations therefore can play a vital role in the improvement of traffic safety. This study illustrates a methodology for evaluation of urban 4-legged signalized intersections treated with left-turn priority phasing. The methodology is applied to three important collisions types: those due to left-turn collisions; those due to left-turn side impact collisions; and all impact types combined collisions. Data used in this analysis were obtained from the City of Toronto. Safety Performance Functions for left-turn and all impact types combined collisions which were developed by the City of Toronto, were calibrated and used in an empirical Bayesian methodology that was employed to estimate the expected frequency of accidents occurring at each intersection in order to evaluate the effectiveness of left-turn priority phasing in reducing this frequency. The results revealed that left-turn priority phasing can be an effective treatment for addressing and reducing the number of collision at signalized intersections. Flashing advance green phasing is more effective in improving safety for two of three types; all left-turn and all impact types combined collisions. Left-turn green arrow (protected/permissive) phasing is more effective for left-turn side impact collisions. By implementing this type of treatment, the number of crashes and the associated monetary loss to society could be significantly reduced.

Queue-Based Guidance for Signalization Consideration at Two and Three-Legged Intersections

2019 ◽  
Vol 2673 (10) ◽  
pp. 416-426
Author(s):  
Shannon Warchol ◽  
Nagui Rouphail ◽  
Chris Vaughan ◽  
Brendan Kearns
Keyword(s):  
North Carolina ◽  
Traffic Control ◽  
Signalized Intersections ◽  
Data Driven ◽  
Left Turn ◽  
Minor Road ◽  
Adjustment Factors ◽  
Queue Lengths ◽  
Control Devices ◽  
A Minor

This research collected and analyzed gap acceptance in North Carolina to develop a data-driven method for determining the need for considering additional signalization analysis at intersections with fewer than four legs. This method can be used for movements that merge with or cross two lanes of oncoming traffic. It is intended to provide guidance and support to traffic engineers in their decision-making process. Charts are provided to determine the expected 95th percentile queue lengths for left-turn, right-turn, and U-turn movements crossing or merging with two lanes of conflicting traffic. This situation is typically present along four-lane roadways where a one-way primary movement opposes either a minor road right-turn movement or a left-turn movement, or in the case of a median U-turn opening. Adjustment factors to the conflicting flowrate were developed to account for the presence of upstream signalized intersections. This method less frequently recommends further signal consideration when compared with the Manual on Uniform Traffic Control Devices peak hour warrant, but is similar to the delay-based level of service D/E threshold for two-way stop-controlled intersections in HCM6 Chapter 19.

scholarly journals Safety Effectiveness of Intersection Left- and Right-Turn Lanes

2003 ◽  
Vol 1840 (1) ◽  
pp. 131-139 ◽  
Author(s):  
Douglas W. Harwood ◽  
Karin M. Bauer ◽  
Ingrid B. Potts ◽  
Darren J. Torbic ◽  
Karen R. Richard ◽  
...  
Keyword(s):  
Traffic Control ◽  
Empirical Bayes ◽  
Matched Pair ◽  
Left Turn ◽  
Before And After ◽  
Accident Data ◽  
Left And Right ◽  
Safety Effectiveness ◽  
Evaluation Approaches ◽  
Control Traffic

The results of research involving a well-designed before-and-after evaluation of the safety effects of providing left- and right-turn lanes for at-grade intersections are presented. Geometric design, traffic control, traffic volume, and traffic accident data were gathered for a total of 280 improved intersections as well as 300 similar intersections that were not improved during the study period. The types of improvement projects evaluated included installation of added left-turn lanes, added right-turn lanes, and extension of the length of existing left- or right-turn lanes. An observational before-and-after evaluation of these projects was performed by using several alternative evaluation approaches. Three contrasting approaches to before-and-after evaluation were used: the yoked comparison or matched-pair approach, the comparison group approach, and the empirical Bayes approach. The research not only evaluated the safety effectiveness of left- and right-turn lane improvements but also compared the performances of these three alternative approaches in making such evaluations. The research developed quantitative safety effectiveness measures for installation design improvements involving added left-turn lanes and added right-turn lanes. The research concluded that the empirical Bayes method provides the most accurate and reliable results. Further use of this method is recommended.

Application of Poisson Underreporting Model to Examine Crash Frequencies at Signalized Three-Legged Intersections

2005 ◽  
Vol 1908 (1) ◽  
pp. 46-50 ◽  
Author(s):  
S. S. P. Kumara ◽  
H. C. Chin
Keyword(s):  
Traffic Control ◽  
Reporting Rate ◽  
Road Accident ◽  
Left Turn ◽  
Factors Affecting ◽  
Surveillance Camera ◽  
Accident Frequency ◽  
Control Factors ◽  
Safety Studies ◽  
Reporting Mechanism

Before effective remedial treatments can be implemented at hazardous intersections, it is often necessary to identify the causal factors affecting accident frequency. However, a problem often encountered in safety studies is the underreporting of accidents. This biased reporting may affect the selection of the parsimonious model. This study analyzes the factors affecting road accident frequency at three-legged signalized intersection approaches in Singapore, with special emphasis to underreporting. The annual accidents at 104 three-legged signalized intersections are modeled as the sum of observed Poisson outcome of accident reports. The reporting mechanism is introduced as a probit equation. The model shows that several geometric, traffic, and traffic control factors significantly affected the accident occurrence. The total approach volumes, left-turn volumes, existence of unprotected left-turn slip roads, number of signal phases per cycle, use of permissive right-turning phase, and sites with sight distances less than 100 m or greater than 300 m appear to increase accident occurrence. However, the presence of right-turn channelization, provision of an acceleration section for left turning, existence of a surveillance camera, availability of median railings, and presence of an approach gradient greater than +5% may reduce the occurrence of intersection approach accidents. Moreover, the study shows that the reporting rate may drop because current law enforcement requires that only injury accidents and accidents at intersections in a residential area be reported.

A Study of an Adaptive Two-Phrase Signal Control Strategy for Resolving Conflicting Transit Signal Priority Calls

2014 ◽  
Vol 505-506 ◽  
pp. 1028-1036
Author(s):  
Liu Yi Gao ◽  
Xiao Jian Hu ◽  
Wei Wang ◽  
Xue Dong Hua
Keyword(s):  
Control Strategy ◽  
Traffic Control ◽  
Simulation Software ◽  
Signal Control ◽  
Transit Signal Priority ◽  
Adaptive Signal Control ◽  
Vehicle Systems ◽  
Micro Simulation ◽  
Travel Delay ◽  
Adaptive Signal

This paper presents the development and evaluation of an adaptive two-phrase signal control strategy to resolve conflicting Transit Signal Priority (TSP) requests. The strategy was designed to provide adaptive transit signal priority control, using vehicle systems and existing traffic control devices. In this paper, the strategys efficiency was tested using a micro-simulation software VISSIM and build one arterial road contains five intersections and serves more than twenty conflicting bus lines. The VAP module was used to control TSP of conflicting requests. In the simulation, actual data was used. Finally, control efficiency about adaptive signal control strategy is discussed. The results show that the presented strategy can improve the operation efficiency of bus corporations. This signal control strategy reduced the travel delay time by 33 % to 55% of transit, while has little impact on private traffic. The strategy shows promising results. In addition, with minor upgrades, it can be applied to any type of intersection.

scholarly journals Unbalanced Multiple Left Turn Lane Usage Modelling: From Individual Choice to Aggregate Volume

2019 ◽  
Vol 2019 ◽  
pp. 1-13
Author(s):  
Li Li ◽  
Qing-Chang Lu ◽  
Dong Zhang ◽  
Ping Wang ◽  
Gui-Ping Wang
Keyword(s):  
Discrete Choice ◽  
Traffic Control ◽  
Choice Model ◽  
Signalized Intersections ◽  
Influential Factors ◽  
Individual Choice ◽  
Left Turn ◽  
Vehicle Type ◽  
Traffic Distribution ◽  
Turning Radius

Diverse lane preferences of left-turn drivers lead to unbalanced traffic distribution on multiple left-turn lanes. The preferences can be measured in terms of lane usage at macroscopic level and individual lane choice at microscopic level. The data of lane volume and individual lane choices are collected at eight dual or triple left-turn lanes equipped in signalized intersections in China. Linear regression model with dummy variables and discrete choice model were applied to analyse drivers’ lane choosing patterns at macroscopic and microscopic levels, respectively, and results of the two studies are mutually verified and complemented. The drivers’ lane preferences are found to vary with approach configurations, traffic control, and the number of lanes available. Static influential factors, such as turning radius inside the intersection, the design of shadowed lane, and intersection skewedness, as well as dynamic influential factors, including queue length, heavy vehicle in queue back and subject vehicle type, could affect the drivers’ lane preferences. The findings of this study have important implications for intersection design and traffic control in practice.

Analysis of Characteristics of Vehicle-Bicycle/Pedestrian Conflicts Using Video Drive Recorder

2011 ◽  
Vol 243-249 ◽  
pp. 4413-4417 ◽  
Author(s):  
Qing Feng Lin ◽  
Bo Cheng ◽  
Guang Quan Lu
Keyword(s):  
Field Test ◽  
Traffic Control ◽  
Road Safety ◽  
Traffic Accidents ◽  
Safety Management ◽  
The Road ◽  
Road Design ◽  
Traffic Conflict ◽  
Accident Data ◽  
One Year

Vehicle to pedestrian/bicycle accidents account for a large proportion of traffic accidents in China. In order to study the characteristics of vehicle to pedestrian/bicycle conflicts, 50 taxis are chosen as the test vehicles. A field-test was conducted using video driver recorder in Beijing for one year. A large amount of traffic conflict and accident data was collected in real driving environment. Considering the factors including conflict type, conflict time, conflict location, traffic control and conflict speed etc., the traffic conflict characteristics of vehicle to pedestrian/bicycle were analyzed. The results might contribute to the road safety management, road design and accident prevention technology.

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