scholarly journals Improving safety and traffic operations in urban zones with a high propensity for rear-end collisions at signalized intersections

2021 ◽  
Author(s):  
Abdul Basit
Keyword(s):  
Traffic Control ◽  
Cycle Length ◽  
Cost Effective ◽  
Signalized Intersections ◽  
Research Report ◽  
Signal Coordination ◽  
High Propensity ◽  
Current Cycle ◽  
Right Turns On Red ◽  
Traffic Operation

At signalized intersections, rear-end accidents are frequently the predominant accident type. These accidents result from the combination of a lead-vehicle's decelereation and the ineffective response of the following vehicle's driver to this deceleration. The frequency and severity of rear end collisions can be reduced through traffic control and operational improvements. There are different traffic operation strategies for rear-end collision reduction like "Employ multiphase signal operation". "optimize clearance intervals" or "Restrict or eliminate turning maneuvers (including right turns on red)". In practice, the most cost-effective strategy appears to be "Employ Signal Coordination". The first objective of this research report was to use spatial analysis tools to disaggregate Toronto into 76 spatial zones (Toronto is usually divided into 158 zones). The second objective was to rank the 76 zones according to their propensity for rear-end collisions at 4-legged signalized intersections. The third objective was to demonstrate how safety can be improved through signal coordination and progression. The software package Synchro-4.00 was used to recommend improved signal coordination through optimization of cycle lenghts, splits and offsets. The coordination analysis for the 15 intersectins located in the zone with the highest propensity for rear-end collision revealed the following results. 1. Coordination was definitely not recommended for three of the intersections. 2. Coordination was probably not recommended for six of the intersections; and 3. Coordination was definitely recommended for six of the intersections. The coordinatability analysis for the 15 intersections located in the zone with the highest propensity for rear-end collisions was performed on the basis of current cycle length (based on field observations). At the nine intersection where coordination is either definitely not recommended or probably not recommended, current cycle length needs to be optimized.

scholarly journals Improving safety and traffic operations in urban zones with a high propensity for rear-end collisions at signalized intersections

2021 ◽  
Author(s):  
Abdul Basit
Keyword(s):  
Traffic Control ◽  
Cycle Length ◽  
Cost Effective ◽  
Signalized Intersections ◽  
Research Report ◽  
Signal Coordination ◽  
High Propensity ◽  
Current Cycle ◽  
Right Turns On Red ◽  
Traffic Operation

At signalized intersections, rear-end accidents are frequently the predominant accident type. These accidents result from the combination of a lead-vehicle's decelereation and the ineffective response of the following vehicle's driver to this deceleration. The frequency and severity of rear end collisions can be reduced through traffic control and operational improvements. There are different traffic operation strategies for rear-end collision reduction like "Employ multiphase signal operation". "optimize clearance intervals" or "Restrict or eliminate turning maneuvers (including right turns on red)". In practice, the most cost-effective strategy appears to be "Employ Signal Coordination". The first objective of this research report was to use spatial analysis tools to disaggregate Toronto into 76 spatial zones (Toronto is usually divided into 158 zones). The second objective was to rank the 76 zones according to their propensity for rear-end collisions at 4-legged signalized intersections. The third objective was to demonstrate how safety can be improved through signal coordination and progression. The software package Synchro-4.00 was used to recommend improved signal coordination through optimization of cycle lenghts, splits and offsets. The coordination analysis for the 15 intersectins located in the zone with the highest propensity for rear-end collision revealed the following results. 1. Coordination was definitely not recommended for three of the intersections. 2. Coordination was probably not recommended for six of the intersections; and 3. Coordination was definitely recommended for six of the intersections. The coordinatability analysis for the 15 intersections located in the zone with the highest propensity for rear-end collisions was performed on the basis of current cycle length (based on field observations). At the nine intersection where coordination is either definitely not recommended or probably not recommended, current cycle length needs to be optimized.

A Dynamic Algorithm of Partitioning Urban Road Network into Traffic Control Subareas

2013 ◽  
Vol 409-410 ◽  
pp. 1398-1402
Author(s):  
Bo Wen Gong ◽  
Yi Ming Bie ◽  
Zhi Yuan Liu
Keyword(s):  
Control Systems ◽  
Traffic Control ◽  
Road Network ◽  
Signalized Intersections ◽  
Dynamic Algorithm ◽  
Urban Road ◽  
Signal Coordination ◽  
Dynamic Factors ◽  
Correlation Degree ◽  
Vehicle Delay

The objective of this study is to develop a dynamic algorithm for traffic control subarea partition. Influencing factors are classified into static factors and dynamic factors. We mainly focus on the three dynamic factors which are cycle length, platoon length and traffic flow continuation. An integrated correlation model is established to quantify the correlation degree of adjacent intersections and then a dynamic partition algorithm is developed based on the model. Both this algorithm and Changs algorithm, which is a representative achievement in subarea partition cited by Traffic control systems Handbook, are applied to a network including 20 signalized intersections in VISSIM to compare their benefits. Statistical results show that: (a) adjacent intersections with high correlation degree can be partitioned into one subarea to execute signal coordination according to our algorithm; (b) implementing our algorithm can save average vehicle delay by 8.9% and average vehicle stops by 7.8% than implementing Changs algorithm.

Estimation of right turn on red saturation flow rates

1995 ◽  
Vol 22 (3) ◽  
pp. 535-543 ◽  
Author(s):  
J. Allen Stewart ◽  
Kirsten Hodgson
Keyword(s):  
Traffic Control ◽  
High Volume ◽  
Signalized Intersections ◽  
Gap Acceptance ◽  
Flow Rates ◽  
Turn On ◽  
Canadian Provinces ◽  
Right Turns On Red ◽  
Saturation Flow ◽  
Right Turns

It is common practice in most Canadian provinces to permit right turns on red at signalized intersections. At intersections with a high volume of pedestrian traffic, the opportunity to turn right on red may be critical to satisfy right turn demand. However, in order to properly time the traffic control signal display at a signalized intersection, the saturation flow rates for each lane or lane group of the intersection must be known. Six signalized intersections were studied in Kingston, Ontario, where saturation flow rates for right turns were measured as a function of conflicting through traffic. From these measurements, estimations of the gap size required for a right turn movement were made. A regression analysis resulted in the production of a simple equation for estimating right turn on red saturation flow rates. It was found that the gap acceptance behaviour of drivers varied both spatially and temporally. Key words: saturation flow rates, signalized intersections, capacity, gap acceptance.

Modeling Capacity of Through Movement at Signalized Intersection Affected by Short Left-Turn Bay under Different Signal Settings

2021 ◽  
pp. 036119812110064
Author(s):  
Zihang Wei ◽  
Yunlong Zhang ◽  
Xiaoyu Guo ◽  
Xin Zhang
Keyword(s):  
Cycle Length ◽  
Signalized Intersections ◽  
Signalized Intersection ◽  
Essential Factor ◽  
Highway Capacity ◽  
Left Turn ◽  
Highway Capacity Manual ◽  
Proposed Model ◽  
Vehicle Demand ◽  
The One

Through movement capacity is an essential factor used to reflect intersection performance, especially for signalized intersections, where a large proportion of vehicle demand is making through movements. Generally, left-turn spillback is considered a key contributor to affect through movement capacity, and blockage to the left-turn bay is known to decrease left-turn capacity. Previous studies have focused primarily on estimating the through movement capacity under a lagging protected only left-turn (lagging POLT) signal setting, as a left-turn spillback is more likely to happen under such a condition. However, previous studies contained assumptions (e.g., omit spillback), or were dedicated to one specific signal setting. Therefore, in this study, through movement capacity models based on probabilistic modeling of spillback and blockage scenarios are established under four different signal settings (i.e., leading protected only left-turn [leading POLT], lagging left-turn, protected plus permitted left-turn, and permitted plus protected left-turn). Through microscopic simulations, the proposed models are validated, and compared with existing capacity models and the one in the Highway Capacity Manual (HCM). The results of the comparisons demonstrate that the proposed models achieved significant advantages over all the other models and obtained high accuracies in all signal settings. Each proposed model for a given signal setting maintains consistent accuracy across various left-turn bay lengths. The proposed models of this study have the potential to serve as useful tools, for practicing transportation engineers, when determining the appropriate length of a left-turn bay with the consideration of spillback and blockage, and the adequate cycle length with a given bay length.

Rural Intelligent Transportation System for Snow Avalanche Detection and Warning

2000 ◽  
Vol 1700 (1) ◽  
pp. 17-23
Author(s):  
Robert Rice ◽  
Rand Decker ◽  
Newel Jensen ◽  
Ralph Patterson ◽  
Stanford Singer
Keyword(s):  
Real Time ◽  
Traffic Control ◽  
Intelligent Transportation System ◽  
Cost Effective ◽  
Warning Systems ◽  
Rural Highways ◽  
Winter Maintenance ◽  
Hazard Reduction ◽  
Maintenance Personnel ◽  
Remaining Time

The growth of winter travel on alpine roads in the western United States, a result of the demand for reliable winter access, has increased the hazard to motorists and highway maintenance personnel from snow avalanches. Configurations are presented for systems that can detect and provide, in real time, warnings to motorists and highway maintainers of roadway avalanches. These warnings include on-site traffic control signing, in-vehicle audio alarms for winter maintenance vehicles, and notifying maintenance facilities or centralized agency dispatchers. These avalanche detection and warning systems can detect an existing avalanche and use the avalanche’s remaining time of descent to initiate on-site alarms. Alternatively, real-time knowledge and notification of the onset of avalanching may be used to proactively manage the evolving hazard over an affected length or corridor of highway. These corridors can be several tens of kilometers in length and may be very remote, low-volume rural highways. As a consequence, these detection and warning systems must be cost-effective alternatives to existing avalanche hazard reduction technology. Results and experiences from the winters of 1997–1998 and 1998–1999 are presented, along with recommendations and criteria for future deployment of these automated natural hazard reduction systems for rural transportation corridors.

scholarly journals Developing a New Spatial Unit for Macroscopic Safety Evaluation Based on Traffic Density Homogeneity

2020 ◽  
Vol 2020 ◽  
pp. 1-9
Author(s):  
Chen Wang ◽  
Lin Liu ◽  
Chengcheng Xu
Keyword(s):  
Traffic Flow ◽  
Traffic Control ◽  
Flow Characteristics ◽  
Traffic Density ◽  
Minimization Method ◽  
Spatial Unit ◽  
Flow Parameters ◽  
Safety Knowledge ◽  
Traffic Operation ◽  
Crash Modeling

Macrolevel crash modeling has been extensively applied to investigate the safety effects of demographic, socioeconomic, and land use factors, in order to add safety knowledge into traffic planning and policy-making. In recent years, with the increasing attention to regional traffic management and control, the safety effects of macrolevel traffic flow parameters may also be of interest, in order to provide useful safety knowledge for regional traffic operation. In this paper, a new spatial unit was developed using a recursive half-cut partitioning procedure based on a normalized cut (NC) minimization method and traffic density homogeneity. Two Bayesian lognormal models with different conditional autoregressive (CAR) priors were applied to examine the safety effects of traffic flow characteristics at the NC level. It was found that safety effects of traffic flow exist at such macrolevel, indicating the necessity of considering safety for regional traffic control and management. Furthermore, traffic flow effects were also examined for another two spatial units: Traffic Analysis Zone (TAZ) and Census Tract (CT). It was found that ecological fallacy and atomic fallacy could exist without considering traffic flow parameters at those planning-based levels. In general, safety needs to be considered for regional traffic operation and the effects of traffic flow need to be considered for spatial crash modeling at various spatial levels.

A Non-Precision Instrument Approach Procedure with Vertical Guidance (IPV) for Aircraft Landing Using GPS

2001 ◽  
Vol 54 (2) ◽  
pp. 281-291 ◽  
Author(s):  
G. Sasi Bhushana Rao ◽  
A. D. Sarma ◽  
V. Venkata Rao ◽  
K. Ramalingam
Keyword(s):  
Traffic Control ◽  
Cost Effective ◽  
Civil Aviation ◽  
Primary System ◽  
Precision Instrument ◽  
Aircraft Landing ◽  
International Civil Aviation Organisation ◽  
Wide Area Augmentation System ◽  
Airport Runway ◽  
Near Future

In the near future, Spaced-Based Augmentation Systems (such as the Wide Area Augmentation System in North America) will become operational, permitting the use of GPS as a primary system for all phases of flight. Recently the International Civil Aviation Organisation (ICAO) has recommended the use of un-augmented GPS as a supplemental navigation system for all phases of flight including non-precision approaches. In this paper, the salient features of the Air Traffic Control (ATC) system in India, and the use of conventional navigational aids are described. A new landing procedure is proposed using un-augmented GPS known as ‘a non-precision instrument approach procedure with vertical guidance (IPV)’ for Hyderabad Airport, Runway 27. This procedure, if implemented, would be cost-effective and reliable for many airports in India. An algorithm has also been developed for determining the range and bearing between the departure and the arrival waypoints of an aircraft using the IPV.

Rural Intelligent Transportation System Natural-Hazard Management on Low-Volume Roads

2003 ◽  
Vol 1819 (1) ◽  
pp. 255-259
Author(s):  
Rand Decker ◽  
Robert Rice ◽  
Steve Putnam ◽  
Stanford Singer
Keyword(s):  
Natural Hazards ◽  
Traffic Control ◽  
Natural Hazard ◽  
Intelligent Transportation System ◽  
Cost Effective ◽  
Intelligent Transportation ◽  
Transportation System ◽  
Hazard Management ◽  
Low Volume ◽  
Road Closure

The growth of winter travel on alpine roads in the western United States has increased the risk to motorists and highway maintenance personnel owing to a variety of natural hazards. Hazards include snow and ice, avalanching snow, and blowing and drifting snow. The conditions call for attendant need for incident response. A substantial number of affected routes are low-volume rural winter roads. Configurations have been developed for rural intelligent transportation system (ITS) technology that can detect hazards and provide, autonomously and in real time, warnings to and traffic control actions for motorists, highway maintainers, and incident responders for roadway natural hazards. These warnings include on-site traffic control signing and road closure gates, in-vehicle audio alarms for agency maintenance and patrol vehicles, and notification to highway agency maintenance facilities or centralized multiagency dispatchers. These actions and notifications are initiated automatically from the remote rural sites and via manual intervention from off-site personnel, well removed from the rural roadway corridor itself. About 5 years of experience have been accumulated in using these rural ITS natural-hazard reduction systems, including snow avalanche detection and warning systems on Loveland Pass, Colorado; Hoback Canyon, Wyoming; and Banner Summit, Idaho. Automated road closure gates on the Teton Pass in Idaho and Wyoming now allow for remote road closure during heavy snow events. These cost-effective ITS natural-hazard systems are highly exportable for other processes that affect rural low-volume roadways, including landslide, flooding, high surf, high winds, loss of visibility, wildlife, and other natural hazards of this type.

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.

Advanced Prediction of Train Arrival and Crossing Times at Highway-Railroad Grade Crossings

2000 ◽  
Vol 1708 (1) ◽  
pp. 68-76 ◽  
Author(s):  
R. Matthew Estes ◽  
Laurence R. Rilett
Keyword(s):  
Traffic Control ◽  
Intelligent Transportation System ◽  
Motor Vehicles ◽  
Practical Reasons ◽  
Test Bed ◽  
Potential Applications ◽  
Grade Crossings ◽  
The Right ◽  
Traffic Operation ◽  
Warning Time

There are many issues related to highway–railroad grade crossings. For historic and practical reasons, trains have the right-of-way at grade crossings, which results in delays to motorists. In addition, the differential in size, speed, and stopping ability between motor vehicles and trains raises many serious safety concerns. Historically, the methods used to address these delay and safety problems at grade crossings have been reactive in nature. For example, the Manual on Uniform Traffic Control Devices specifies a minimum of 20 s of warning time for active warning devices at grade crossings. Intelligent transportation system (ITS) technology offers potential solutions for increasing the warning time at grade crossings. Advanced on-board devices and off-track detection equipment can allow train position and speed to be monitored. This information can be shared through wireless and wireline telecommunications equipment being deployed for ITS. Transportation management center personnel can then predict the arrival and crossing times of trains at grade crossings. It is hypothesized that if the warning time could reliably be increased, the traffic-operation strategies in the vicinity of grade crossings could be more proactive, reducing delay to motorists and increasing safety for both trains and automobiles. The research focuses on a second-generation technology approach to an advanced prediction of train arrival and crossing (gate-up and gate-down) times at highway–railroad grade crossings, including problems faced at grade crossings, background on detection and prediction technology for grade crossings, the train monitoring system used as the test bed for the research, the development of the methodology, the results of the analysis, and the conclusions of the research and potential applications for the model.

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