Pedestrian Safety at Intersections under Control of Permissive Left-Turn Signal

2012 ◽  
Vol 2299 (1) ◽  
pp. 91-99 ◽  
Author(s):  
Yi Qi ◽  
Peina Yuan
Keyword(s):  
Pedestrian Safety ◽  
Left Turn ◽  
Turn Signal

Driver Age as a Factor in Comprehension of Left-Turn Signals

1997 ◽  
Vol 1573 (1) ◽  
pp. 76-85 ◽  
Author(s):  
Aris Drakopoulos ◽  
Richard W. Lyles
Keyword(s):  
Correct Answer ◽  
Explanatory Variable ◽  
Age Groups ◽  
Error Rates ◽  
Original Study ◽  
Older Drivers ◽  
Left Turn ◽  
Turn Signal ◽  
Right Of Way ◽  
Signal Operations

An experiment to measure driver comprehension of left-turn signal and sign configurations was conducted as part of a study to investigate the performance of left-turn signals used in various signal strategies. The responses of 191 individuals to 81 stimuli simulating left-turn signal phases were analyzed for the effect of signal message on driver comprehension. Stimuli included 17 left-turn signal displays used for permitted, protected, and protected/permitted left-turn strategies as well as left turns during nighttime or emergency flashing signal operations. Comprehension in the original study was based on a correct versus incorrect dichotomy: if the subject’s response agreed with a predetermined subset of possible answers, the answer was correct; all other answers were considered incorrect. These data are reanalyzed with three principal variations: ( a) individuals’ answers are based on a three-level correctness concept whereby answers considered incorrect in the previous study were further categorized into minor errors and serious errors depending on whether subjects incorrectly chose to “give away” their right-of-way or to violate other drivers’ right-of-way, respectively; ( b) signal message is introduced in the analysis as an explanatory variable of driver comprehension; and ( c) emphasis is placed on older drivers. Youngest, oldest, and female subjects were found to drive fewer kilometers per year than middle-aged males. Comprehension was found to deteriorate with driver age in terms of both higher serious error rates and lower correct answer rates. Flashing signals were the least well understood, whereas change and red interval stimuli were understood best by all age groups.

A Laboratory Investigation of Signal Indications for Protected Left Turns

1974 ◽  
Vol 16 (1) ◽  
pp. 37-45 ◽  
Author(s):  
Ralph W. Plummer ◽  
L. Ellis King
Keyword(s):  
Motion Picture ◽  
Reaction Times ◽  
Major Objective ◽  
Motion Picture Film ◽  
Male And Female ◽  
Left Turn ◽  
Turn Signal ◽  
Different Types ◽  
The Subject ◽  
Left Turns

The major objective of this research was to investigate and compare driver comprehension and understanding of different types of left-turn signal clearance indications for protected left turns. Forty subjects, male and female drivers, were tested. The test utilized color slides and color motion-picture film segments to present the subject with both steady and flashing left-turn signal indications. After each presentation of a signal indication, the subject responded by pressing one of three answer buttons. Accuracy and reaction times of each response were recorded. The results of this investigation recommended that three signal sequences be field tested as they conveyed their intended messages to the subjects more efficiently than the remaining eleven. The results also indicated that none of the three flashing signals tested proved to be effective.

scholarly journals An Evaluation of Leading Versus Lagging Left Turn Signal Phasing

1989 ◽  
Author(s):  
Joseph Hummer ◽  
Robert Montgomery ◽  
Kumares Sinha
Keyword(s):  
Left Turn ◽  
Turn Signal

Effects of Inadequate Driveway Corner Clearances on Traffic Operations, Safety, and Capacity

1997 ◽  
Vol 1579 (1) ◽  
pp. 35-42 ◽  
Author(s):  
Cheng-Tin Gan ◽  
Gary Long
Keyword(s):  
Conflict Analysis ◽  
Traffic Operations ◽  
Inventory Data ◽  
Flow Rates ◽  
Left Turn ◽  
Turn Signal ◽  
Arterial Streets ◽  
Operational Safety ◽  
Traffic Conflict ◽  
Saturation Flow

Inadequate driveway corner clearances can result in traffic operational, safety, and capacity problems. These problems can be caused by blocked driveway ingress and egress movements, incomplete turning maneuvers, conflicting intersection turning movements, confusing right-turn signal indications, insufficient weaving and merging section lengths, and various other conflicts. The effects of driveway corner clearances on safety cannot be examined easily through safety records given the current condition of the available crash and system inventory data. This provides incentives for applying theoretical traffic conflict analysis. A simple conflict analysis showed an increase in merging and crossing conflict points for driveways situated near intersections. Inadequate corner clearance can have a capacity-reducing effect. Driveway capacity may be reduced by ( a) vehicles on the arterial blocking driveway egress movements and ( b) a decreased opportunity for left-turn egress movement on arterial streets designed for platoon progression. Intersection capacity can also be reduced by a decrease in saturation flow rates due to driveway ingress and egress movements.

Safety Performance of Flashing Yellow Arrow for Protected–Permissive Left-Turn Signal Control in Central Illinois

2017 ◽  
Vol 2636 (1) ◽  
pp. 32-42 ◽  
Author(s):  
Kerrie L. Schattler ◽  
Eric P. Anderson ◽  
Trevor Hanson
Keyword(s):  
Empirical Bayes ◽  
Safety Evaluation ◽  
Left Turn ◽  
Turn Signal ◽  
Crash Data ◽  
Flashing Yellow Arrow ◽  
Before And After ◽  
Control Research ◽  
Central Illinois ◽  
Yellow Arrow

In 2010, the Illinois Department of Transportation began implementing the flashing yellow arrow (FYA) at intersections operating with protected–permissive left-turn (PPLT) control. Research was conducted to evaluate the safety-effectiveness of FYAs at 86 intersections and 164 approaches in central Illinois. The effectiveness evaluation was performed with 3 years of before-and-after FYA installation crash data and the empirical Bayes method. In the before condition, the left-turn signals operated with a circular green display indicating the permissive interval of PPLT control using a five-section signal head. In the after condition, the FYA replaced the circular green display for the permissive interval of PPLT with a four-section signal head. Supplemental traffic signs were mounted on the mast arm adjacent to the left-turn signal at over half of the FYA installations. The results of the comprehensive safety evaluation of the FYA for PPLT control are presented. Analyses were also performed to assess the effects of the FYA supplemental signs and the effects of the FYA overall on two subsets of at-fault drivers: older drivers (age 65+) and younger drivers (age 16 to 21). The resulting mean crash modification factors for the targeted crash types ranged from 0.589 to 0.714. The findings of this research support the continued use of FYAs for PPLT control to improve safety at signalized intersections in central Illinois.

scholarly journals Using microsimulation and crashes to evaluate the safety of left turn lanes at rural signalized intersections

2021 ◽  
Author(s):  
Nima Farid
Keyword(s):  
Signalized Intersections ◽  
Research Topic ◽  
Safety Performance ◽  
Left Turn ◽  
Related Research ◽  
Turn Signal ◽  
Combined Impact

Left turn movements at intersections can be particularly unsafe. One treatment aimed at making the movement safer is the provision of left turn lanes. However, there is a missing piece in the related research, specifically how the length of left turn lanes impacts the safety of intersections. The Ministry of Transportation Ontario (MTO) has defined this as a high priority research topic. There were two major objectives in this research, both of which were addressed with microsimulation. The first was to determine a relationship between a length of left-turn lanes and safety performance of an intersection, and second was to examine the combined impact of simultaneous installation of left turn lanes with varying lengths and protected left-turn signal phasing. The findings suggested that the longer a left turn lane is, the safer the intersection would be, especially with regard to rear-end crashes.

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