Effect on Vehicle-Pedestrian Conflicts of “Turning Traffic Must Yield to Pedestrians” Sign

1996 ◽  
Vol 1553 (1) ◽  
pp. 38-45 ◽  
Author(s):  
Husham N. Abdulsattar ◽  
Mohammed S. Tarawneh ◽  
Patrick T. McCoy ◽  
Stephen D. Kachman
Keyword(s):  
Traffic Control ◽  
Signalized Intersections ◽  
Legal Obligation ◽  
Left Turn ◽  
Right Of Way ◽  
Two Cities ◽  
Before And After ◽  
Left And Right ◽  
Control Devices ◽  
The Right

Left- and right-turn movements at signalized intersections have been found to be three to six times more hazardous to pedestrians than through movements mainly because drivers fail to observe or yield the right of way to pedestrians. The objective was to evaluate the Turning Traffic Must Yield to Pedestrians sign, which was aimed at reminding turning motorists of their legal obligation to yield the right of way to pedestrians and, consequently, reducing vehicle-pedestrian conflicts. The sign was installed at 12 marked crosswalks in two cities, and vehicle-pedestrian conflict data were collected before and after its installation. The sign was effective in reducing left-turn conflicts 20 to 65 percent and right-turn conflicts 15 to 30 percent; both reductions were statistically significant at the 0.05 level. The sign was significantly more effective in reducing left-turn conflicts than it was for right-turn conflicts. Percentage conflicts between pedestrians and turning traffic decreased as the pedestrian group size increased. In other words, larger pedestrian group sizes encountered fewer conflicts with turning traffic. This result is true for both left- and right-turn movements, regardless of the presence of the sign. Based on the results of this study, it was recommended that the “Turning Traffic Must Yield to Pedestrians” sign be considered for inclusion in the Manual on Uniform Traffic Control Devices.

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.

Field Evaluation of a Leading Pedestrian Interval Signal Phase at Three Urban Intersections

2000 ◽  
Vol 1734 (1) ◽  
pp. 86-92 ◽  
Author(s):  
Ron Van Houten ◽  
Richard A. Retting ◽  
Charles M. Farmer ◽  
Joy Van Houten
Keyword(s):  
Public Education ◽  
Traffic Control ◽  
Field Evaluation ◽  
Signal Phase ◽  
Right Of Way ◽  
Pedestrian Injury ◽  
Pedestrian Traffic ◽  
Control Devices ◽  
Pedestrian Crashes ◽  
The Right

About 37 percent of pedestrian injury crashes and 20 percent of fatal pedestrian crashes occur at intersections. Many conventional countermeasures include traffic control devices that either increase pedestrian attention to potential vehicle-pedestrian conflicts or encourage drivers to yield to pedestrians. A noteworthy limitation of these warning and prompting messages is their reliance on a voluntary behavioral response. Public education and enforcement campaigns have also generally not produced tangible and long-lasting safety benefits. This research, conducted at three urban intersections, examined the influence of a 3-s leading pedestrian interval (LPI)—a brief and exclusive signal phase dedicated to pedestrian traffic—on pedestrian behavior and conflicts with turning vehicles. The introduction of a 3-s LPI reduced conflicts between pedestrians and turning vehicles and reduced the incidence of pedestrians yielding the right-of-way to turning vehicles.

scholarly journals Impact of using indirect left-turns on signalized intersections’ performance

2017 ◽  
Vol 44 (6) ◽  
pp. 462-471 ◽  
Author(s):  
Mahmoud Taha ◽  
Akmal Abdelfatah
Keyword(s):  
Traffic Control ◽  
Urban Areas ◽  
Signalized Intersections ◽  
Superior Performance ◽  
Operational Performance ◽  
Left Turn ◽  
Traffic Conditions ◽  
Traffic Delays ◽  
The Right ◽  
Transportation Agencies

The majority of traffic delays in urban areas occur at signalized intersections. Due to the limited availability of space and right-of-way, many transportation agencies are considering unconventional traffic control systems for intersections to improve signal efficiency and reduce overall delays. Common unconventional left-turn treatments include the right-turn followed by a U-turn (RTUT) and a U-turn followed by a right-turn (UTRT). The main goal of this study is to determine the traffic operational performance of the three left-turn treatments under different traffic conditions. The results showed that unconventional left-turn control types have less delay and travel time compared to the direct left-turn (DLT), when the U-turn locations are 200 m away from the main intersection. Also, RTUT showed superior performance over the other left-turn control types, when the U-turn locations are 100 m away from the main intersection.

Safety Service Patrol Uniforms: Technology, National Practices, and Operator Preferences

2019 ◽  
Vol 2673 (11) ◽  
pp. 456-465
Author(s):  
Grady Carrick ◽  
Katherine Belmore
Keyword(s):  
United States ◽  
Traffic Control ◽  
National Level ◽  
Past Research ◽  
The United States ◽  
Right Of Way ◽  
Technical Requirements ◽  
Control Devices ◽  
The Right ◽  
Almost All

Safety service patrols operate in more than 40 states and territories in the United States and each program operates with unique vehicles, uniforms, and equipment. Despite the variety of operator uniforms, legal and technical requirements at a national level dictate some choices, though color and style are largely at the discretion of states. Past research confirms that high-visibility safety apparel (HVSA) increases visibility. Biomotion markers on the joints further enhance visibility. The Manual on Uniform Traffic Control Devices specifies that personnel working in the right-of-way wear a Class 2 or 3 HVSA. A survey of states where service patrols operate found the majority use high-visibility yellow-green over red-orange, and Class 3 garments are preferred over Class 2. In relation to the base uniform, there is a mixture of maintenance-type uniforms, polo shirts, and no uniform specification at all. In a survey of Florida service patrol program managers and operators, conveying professionalism, comfort, and safety were the most valued aspects of uniforms. Operators understand the need to care and maintain HVSA, but may overestimate their ability to be seen at night by between two and four times the actual distance they are visible. When given a choice, operators preferred dark trousers with biomotion markers, though they were roughly split between the polo shirt/vest option and the integrated HVSA shirt that does not require use of a vest. A uniform protective outerwear was favored by almost all operators, and a ball cap was the headwear of choice.

scholarly journals Effect of dental wear, stabilization appliance and anterior tooth reconstruction on mandibular movements during speech

2008 ◽  
Vol 19 (2) ◽  
pp. 151-158 ◽  
Author(s):  
Priscila de Oliveira Serrano ◽  
Fernanda Faot ◽  
Altair Antoninha Del Bel Cury ◽  
Renata Cunha Matheus Rodrigues Garcia
Keyword(s):  
Tooth Wear ◽  
Anterior Tooth ◽  
Control Group ◽  
Dental Wear ◽  
Jaw Opening ◽  
Before And After ◽  
Left And Right ◽  
The Right ◽  
Tracking Device ◽  
Mandibular Movements

This study described changes in mandibular movements during pronunciation of /m/ and /s/ sounds in Portuguese, in patients presenting dental wear before and after appliance insertion and tooth reconstruction. Subjects were divided into a control group of dentate patients and an experimental group of patients with incisal tooth wear due to bruxism. A magnetic jaw tracking device measured the jaw opening, and translations to left and right sides of the mandible during pronunciation of phonemes. Evaluations were carried out 1 week and immediately before appliance insertion; 24 h, 7, 30 and 60 days after appliance insertion; and 1 week and 1 month after tooth reconstruction. Data were submitted to two-way ANOVA, Mann-Whitney and Friedman tests (p<0.05). Jaw opening was different (p<0.05) for both sounds in all periods. The anteroposterior amplitude for /s/ showed differences immediately before and 1 month after appliance insertion (p<0.05). Lateral amplitude for the right side showed differences between groups after appliance insertion for /s/, and 1 and 2 months after appliance insertion for the /m/ (p<0.05). Volunteers with anterior tooth wear had a wider opening movement, and the movements during speech of /m/ and /s/ sounds were not changed after appliance insertion and reconstruction of teeth.

Developing and Implementing Manual on Uniform Traffic Control Devices Criteria for Selecting Traffic Control for Unsignalized Intersections

2019 ◽  
Vol 2673 (11) ◽  
pp. 319-331
Author(s):  
H. Gene Hawkins ◽  
Kay Fitzpatrick ◽  
Marcus A. Brewer
Keyword(s):  
Traffic Control ◽  
Traffic Engineering ◽  
High Speed ◽  
Research Team ◽  
Right Of Way ◽  
Unsignalized Intersections ◽  
Control Devices ◽  
Traffic Control Devices ◽  
Urban Conditions ◽  
Selection Of

The 2009 United States Manual on Uniform Traffic Control Devices (MUTCD) includes guidance for the use of various types of traffic control at unsignalized intersections. Despite changes and advances in traffic engineering in recent decades, the MUTCD content related to selection of traffic control in Part 2B has seen only minor changes since 1971. The types of unsignalized traffic control addressed in the current research included no control, yield control, two-way stop control, and all-way stop control. The research team developed recommendations using information available from reviews of existing literature, policies, guidelines, and findings from an economic analysis along with the engineering judgment of the research team and panel. The researchers then developed recommended language for the next edition of the MUTCD for unsignalized intersections. This includes consideration of high-speed (rural) and low-speed (urban) conditions along with the number of legs at the intersection. Because the number of expected crashes at an intersection is a function of the number of legs, the decision on appropriate traffic control should also be sensitive to the number of legs present. The proposed language includes introductory general considerations, discusses alternatives to changing right-of-way control, and steps through the various forms of unsignalized control from least restrictive to most restrictive, beginning with no control and concluding with all-way stop control.

scholarly journals Hemispheric Lateralization of Pain Processing by Amygdala Neurons

2009 ◽  
Vol 102 (4) ◽  
pp. 2253-2264 ◽  
Author(s):  
Guangchen Ji ◽  
Volker Neugebauer
Keyword(s):  
Receptive Fields ◽  
Hemispheric Lateralization ◽  
Central Nucleus ◽  
Recording Site ◽  
Peripheral Tissues ◽  
Arthritis Induction ◽  
Before And After ◽  
Pain State ◽  
Left And Right ◽  
The Right

Recent biochemical and behavioral data suggest right-hemispheric lateralization of amygdala functions in pain. Our previous electrophysiological studies showed pain-related neuroplasticity in the latero-capsular division of the central nucleus of the amygdala (CeLC) in the right brain hemisphere. Here we determined differences in the processing of pain-related signals in right versus left CeLC neurons. Individual CeLC neurons were recorded extracellularly before and after induction of an arthritis pain state in anesthetized rats. Brief innocuous and noxious test stimuli were applied to peripheral tissues ipsi- and contralateral to the recording site. A monoarthritis was induced in the ipsi- or contralateral knee by intraarticular injections of kaolin and carrageenan. Under normal conditions, CeLC neurons in the left amygdala had smaller receptive fields than those in the right, but the magnitude of background and evoked activity was not significantly different. After arthritis induction, neurons in the right, but not left, CeLC developed increased background activity and evoked responses, irrespective of the location of the arthritis (ipsi- or contralateral to the recording site). A protein kinase A (PKA) inhibitor decreased the activity of right CeLC neurons after arthritis induction but had no effect in the left amygdala. Forskolin, however, increased the activity of left and right CeLC neurons under normal conditions. The results show for the first time laterality of pain-related electrophysiological activity changes in individual amygdala neurons. Whereas both left and right amygdala neurons receive nociceptive inputs and can become sensitized in principle, a yet unknown mechanism prevents PKA activation and pain-related changes in the left amygdala.

Bottleneck Simulation of Two-Lane Traffic CA Model with Turn Signal

2013 ◽  
Vol 404 ◽  
pp. 640-644
Author(s):  
Rui Kang ◽  
Kai Yang
Keyword(s):  
Numerical Simulations ◽  
Traffic Flow ◽  
Traffic Congestion ◽  
Driver Behavior ◽  
Traditional Model ◽  
Right Of Way ◽  
Time Space ◽  
Before And After ◽  
Ca Model ◽  
The Right

Based on the STCA model, an improved two-lane traffic CA model in view of turn signals is proposed. The model considers changes in driver behavior before and after the signaling of the leading vehicle, and introduces rules of changing lanes, cutting lanes and yielding the right of way for the flowing vehicle. Through computer numerical simulations, this study has presented time-space diagrams and also analyzed the effects of driver behavior of the rear vehicles on traffic flow. The results reveal that a higher rate of cutting lanes incurs a heavier traffic flow in normal situations while yielding the right of way relieves traffic congestion in a bottleneck situation. Compared with the traditional model, STCA model can depict more complex traffic situations resulted from different driver behaviors and reproduce a more realistic process of traffic flow.

Operational Impact of Split Intersections

1997 ◽  
Vol 1579 (1) ◽  
pp. 73-78 ◽  
Author(s):  
Abishai Polus ◽  
Ronen Cohen
Keyword(s):  
Minimum Distance ◽  
Signalized Intersections ◽  
Left Turn ◽  
Suburban Areas ◽  
Advantages And Disadvantages ◽  
Minor Road ◽  
Lost Time ◽  
The Right ◽  
The Impact ◽  
Operational Impact

High volumes at urban and suburban intersections may cause considerable delay to vehicles during the peak periods, particularly when the left-turning volume is combined with high through volumes in both directions. The operational impact resulting from converting a major conventional cross intersection into two smaller signalized intersections is analyzed and evaluated. The two intersections are constructed along the minor road, allowing the left-turn movement from the major road to operate simultaneously with the through movement and to be stored in more lanes on the minor road. The general advantages and disadvantages of a split intersection are discussed. It is shown that the split increases capacity because of better efficiency resulting from ( a) the smaller geometry of each intersection, which reduces “lost time,” compared to the geometry of a single larger intersection, ( b) a reduction in the number of signal phases from four to three and an increase in the effective green time for all movements, and ( c) an increase in the number of lanes available for storage of the left-turn movement. It is also shown that delay is reduced, particularly when the flow is close to saturation. The impact of the cycle length and the left-turn volume is evaluated. Further analysis ascertains the minimum distance between the two smaller intersections under two scenarios: ( a) a minimum distance for storage of the left-turn movement and ( b) a longer distance to reduce delays and to allow for the simultaneous start of the green time for the through movements in the two intersections. It is concluded that the longer distance is feasible mainly for new intersections in suburban areas where the right of way is available.

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