Pedestrian Phase Research Articles

Modifying Highway Capacity Manual Methodology for Inclusion of Flashing-Yellow-Arrow Delay and Suppression

Dallas phasing is an effective strategy for increasing the efficiency of protected-permissive left turns (PPLTs) at signalized intersections, without creating left-turn traps. The flashing yellow arrow (FYA) is the most widely used PPLT signal indication when Dallas phasing is utilized. The Highway Capacity Manual (HCM) signalized intersection methodology currently contains guidance on how to handle PPLTs with Dallas phasing. At intersections with the FYA indication, some agencies have been using a feature known as FYA delay, which delays the FYA indication, usually by 1 to 4 s. More recently, some agencies have also began using another feature, which suppresses the FYA when a conflicting pedestrian phase is active. The HCM does not contain guidance on how to handle FYA delay or suppression. This research proposed modifications to the HCM signalized intersection methodology to address these two FYA strategies. A sensitivity analysis was conducted to check the reasonableness of the proposed modifications. The sensitivity analysis showed that the proposed modifications are reasonable and produced the expected results.

Simulation-Based Evaluation of a New Integrated Intersection Control Scheme for Connected Automated Vehicles and Pedestrians

In a fully connected traffic environment with automated vehicles, new traffic control strategies could replace traditional traffic signals at intersections. In recent years, several studies about reservation-based intersection control strategies have been published, and a significant increase in capacity was shown. In the strategies presented so far, other road users usually play a minor role or are not considered at all. However, many use cases of automated driving occur in urban environments, where pedestrians and bicyclists play a major role. In this paper, a novel strategy for integrating pedestrians into automated intersection management is introduced and compared with a fully actuated traffic (AT) signal control. The presented control consists of a first-come, first-served strategy for vehicles in combination with an on-demand traffic signal for pedestrians. The proposed intersection control is explained, implemented, and tested on a four-leg intersection with several lanes coming from each direction. It dynamically assigns vehicles to lanes, and vehicles follow a protocol that enables cooperative lane-changing on the approach to the intersection. Demand-responsive pedestrian phases are included in such a way that predefined maximum pedestrian waiting times are not exceeded. A set of demand scenarios is simulated using a microsimulation platform. The evaluation shows that the presented control performs significantly better than the AT control when considering low, medium, and high traffic demand. Pedestrian waiting times are slightly improved and at the same time vehicle delays are substantially decreased. However, the control needs to be improved for scenarios with a very high vehicle demand.

Using Stochastic Variation of Cyclic Green Distributions to Populate SAE J2735 Message Confidence Values along a Signalized Corridor

The communication between connected vehicles and traffic signal controllers is defined in SAE Surface Vehicle Standard J2735. SAE J2735 defines traffic signal status messages and a series of 16 confidence levels for traffic signal transitions. This paper discusses a statistical method for tabulating traffic signal data by phase and time of day and populating the SAE J2735 messages. Graphical representations of the red–green and green–yellow transitions are presented from six intersections along a 4-mile corridor for five different time-of-day timing plans. The case study provided illustrates the importance of characterizing the stochastic variation of traffic signals to identify locations, phases, and time-of-day periods when traffic indications operate with high predictability. Specific cases, such as low vehicle demand and occasional actuation of pedestrian phases are highlighted as situations that may reduce the predictability of traffic signal change intervals. The results from this study also open up discussion among transportation professionals on the importance of consistent tabulation of confidence values for both beginning and end of green signal states. We believe this paper will initiate dialog on how to consistently tabulate important data elements transmitted in SAE J2735 and perhaps refine those definitions. The paper concludes by highlighting the importance of traffic engineers and connected vehicle developers to work together to develop shared visions on traffic signal change characteristics so that the in-vehicle use cases and human–machine interface meet user expectations.

Modelling and Simulation of Urban Mobile Agents for Analyzing Mixed Flows in Urban Pedestrian Space

Since the 1990s, complex systems research has been developing agent simulations to explain the phenomena observed in urban spaces. In recent years, agent-based modelling has often been employed to successfully simulate pedestrian behaviour. In such studies, explanations using pedestrian counter flow phases have appeared sporadically. Most state-of-the-art models, however, do not generally consider mobile agents other than pedestrians or counter flows in at least two directions. In this paper, we consider agents such as pedestrians, vehicles, wheelchairs, bicycles and so on in urban pedestrian space (UPS), which we call urban mobile agents (UMAs). The aim of this research is to develop a simulation platform to support urban simulation research. The models of rule-based UMAs that we have been developing are used to analyze the micro-meso behaviours of the mixed flows in UPS. The content of this class of agent includes the pedestrian agent as per the simplified agent simulation of pedestrian flow (sASPF) rules as well as the vehicle agent and bicycle agent in the UPS, including a wheelchair agent in the coming research. Using these models, we explore the following approaches: (a) theoretical analyses of phase transitions such as laminar flow formation or blockade of pedestrian counter flows, with clarification of the relationship between the degree of pedestrian global density and the bias of the diagonal stepping probability, which is the right or left selection probability of avoidance behaviour; (b) the implementation of obstacle avoidance rules in the sASPF pedestrian agent model, and their comparison with published evacuation experiment results, so as to evaluate the performance of the obstacle avoidance function; (c) the development of a vehicle agent model to simulate pedestrian-vehicle mixed flow at a crossroads assuming a disaster scenario; (d) the development of a bicycle agent model by extending sASPF rules; and (e) consideration of a conceptual framework for interaction fields representing heterogeneous agent mixed flows, including vehicle, bicycle, pedestrian and wheelchair agents.

A comprehensive study on factors influencing pedestrian signal violation behaviour: Experience from Kolkata City, India

Signalized intersections with marked crosswalks enhance pedestrian safety by providing the designated right of way to pedestrians. However, a significant number of pedestrian crashes occur at signalized intersections, which may predominantly be due to pedestrians’ violation behaviors. Therefore, it is worthwhile to examine how pedestrian risk and signal violation are associated. For this purpose, pedestrians’ crossing behavior, and perception data have been collected from 55 signalized junctions in Kolkata, India, and a mathematical relationship is developed between the share of pedestrian signal violation and the frequency of fatal pedestrian crashes. The model outcome indicates that there is a significant and positive association between these two variables. Subsequently, with the help of “beta regression model” it is identified that absence of pavement marking, traffic cycle length, inadequate sight distance, on-street parking, a high share of pedestrian carrying overhead loads, pedestrian’s intended mode of transport after crossing, and pedestrian’s sociodemographic characteristics significantly influence the share of pedestrian signal violation behavior. The study finding indicates that while improvement in the design of the built environment and signal settings to increase pedestrians’ convenience and confidence are must, and there is a crucial need to integrate innovative safety management practices to address spatial and temporal needs of an intersection. For example, intersections with high commercial activities generating a high volume of pedestrian carrying overhead goods demand particular pedestrian phase with countdown signals. Further, to control pedestrians’ unruly behavior, adequate pavement marking, zebra crossing, designated bus stop facility, pedestrian signal head, and off-street parking facility should be provided along with the strict enforcement. Moreover, to enhance compliance with traffic signals, road safety campaigns, education, and awareness programs are must for better and safer road use.

Enhancing pedestrian safety, walkability and traffic flow with fuzzy logic

The continuous congestion in the Arabian Gulf Road, located in Kuwait, contributes to air pollution in the area and causes discomfort for both drivers and pedestrians. The objective of this work is to enhance walkability and safety of pedestrians in the Gulf road while facilitating traffic flow. The study had been conducted for the road and surrounding area staring from the Society of Engineers till the British Embassy. Two methods were established to enhance walkability at each intersection. The first method used Synchro software to improve the traffic condition, lessen the delay time, and add pedestrian phase for each intersection. In the second method, fuzzy logic code was scripted using MATLAB to adjust traffic lights duration, for creating an adaptive traffic system. The best-established solution for traffic phasing at the Engineering Society intersection was mitigation scenario one, which contributed to decreasing the delay time by 63.82%, reaching only 5 min of delay. As for the British embassy intersection, the delay had been reduced by 11.82% using mitigation scenario 2. Several adjustments had been implemented in the study area that included replacing the current parking space with a wide green area, adding underground parking, and designating a particular lane for bicycles. The green area was provided with a shaded pathway using photovoltaic panels, jugging pathway, retail shops, and playing grounds to encourage walkability and reduce dependence on vehicles. A LEED-certified restaurant model had been designed that scored a gold certificate. Two additional restaurants were proposed in the area and a pond to attract more visitors.

Multi-Stage Pedestrian Crossings and Two-Stage Bicycle Turns: Delay Estimation and Signal Timing Techniques for Limiting Pedestrian and Bicycle Delay

Signalized intersections sometimes involve multistage pedestrian crossings, in which pedestrians cross to one or more islands and then wait there for a signal to continue. When signals are timed without attention to pedestrian progression, pedestrian delay at multistage crossings can be very long. This paper addresses two issues. First, pedestrian delay at multistage crossings is rarely evaluated because there are no tools in the industry for that purpose except microsimulation. We present a numerical method for determining crossing delay with any number of stages and with the possibility of multiple WALK intervals per cycle. The same method can be applied to single stage crossings, to diagonal two-stage crossings where pedestrians may have path choice, and bicycle two-stage turns. This method has been implemented in a freely available online tool. Second, we describe several signal timing techniques for improving pedestrian and bicyclist progression, and thus reducing their delay, through multistage crossings. They include reservice for selected crossing phases, left turn overlaps, having pedestrian phases overlap each other, and bidirectional bicycle crossings which create path options for two-stage turns. Examples show the potential for large reductions in pedestrian delay, often with little or no increase in vehicular delay. In one example, the addition of a short pedestrian overlap phase reduced average pedestrian delay at a 3-stage crossing by 82 s while average vehicular delay increased by only 0.5 s.

Individuals with severely impaired vision can learn useful orientation and mobility skills in virtual streets and can use them to improve real street safety.

Virtual reality has great potential in training road safety skills to individuals with low vision but the feasibility of such training has not been demonstrated. We tested the hypotheses that low vision individuals could learn useful skills in virtual streets and could apply them to improve real street safety. Twelve participants, whose vision was too poor to use the pedestrian signals were taught by a certified orientation and mobility specialist to determine the safest time to cross the street using the visual and auditory signals made by the start of previously stopped cars at a traffic-light controlled street intersection. Four participants were trained in real streets and eight in virtual streets presented on 3 projection screens. The crossing timing of all participants was evaluated in real streets before and after training. The participants were instructed to say “GO” at the time when they felt the safest to cross the street. A safety score was derived to quantify the GO calls based on its occurrence in the pedestrian phase (when the pedestrian sign did not show DON’T WALK). Before training, > 50% of the GO calls from all participants fell in the DON’T WALK phase of the traffic cycle and thus were totally unsafe. 20% of the GO calls fell in the latter half of the pedestrian phase. These calls were unsafe because one initiated crossing this late might not have sufficient time to walk across the street. After training, 90% of the GO calls fell in the early half of the pedestrian phase. These calls were safer because one initiated crossing in the pedestrian phase and had at least half of the pedestrian phase for walking across. Similar safety changes occurred in both virtual street and real street trained participants. An ANOVA showed a significant increase of the safety scores after training and there was no difference in this safety improvement between the virtual street and real street trained participants. This study demonstrated that virtual reality-based orientation and mobility training could be as efficient as real street training in improving street safety in individuals with severely impaired vision.

Investigation of Self-Organizing Traffic Signal Control with Graphical Signal Performance Measures

Adaptive signal control is the subject of an increasing amount of research, development, and implementation. Most existing adaptive control systems achieve coordination by applying system control as a constraining layer on top of local control. Some researchers have suggested that, with the right local control logic, coordination might be achieved as a dynamically emergent phenomenon without the need for a management layer. This paper describes how the potential of a self-organizing signal control algorithm was explored with various performance measures. First, the initially reported algorithm performance was reproduced in an idealized environment; next, the algorithm was applied in a realistic road network to compare its performance with that of actuated coordinated control, with and without pedestrian phases. Comparisons were made under ( a) the same base volumes used to design the actuated coordinated timing plan and ( b) variant volumes. Self-organizing control was found to be more flexible than coordinated control and induced a performance trade-off between movement types. Delay reductions of 38% to 56% were observed in an environment with no pedestrian phase. However, with pedestrian phases in recall, self-organizing control performed worse (39% increase in delay) under base volumes and achieved a weak benefit (6% reduction in delay) under variant volumes. Because of the large total delay reductions in some scenarios, the results show promise for future development.

Validation of an Agent-Based Microscopic Pedestrian Simulation Model at a Scramble Phase Signalized Intersection

Recently, an agent-based pedestrian simulation model was developed at the University of British Columbia to model detailed pedestrian interactions. The model was originally calibrated and validated with video data, collected at a signalized intersection in Vancouver. However, it is important to investigate the applicability of the model in different walking environments. The main objective of this study was to assess the model performance in handling pedestrian interactions at a scramble phase signalized intersection in Oakland, California. The intersection had four conventional crosswalks in addition to two diagonal crosswalks, used during the scramble pedestrian phase. Model parameters were calibrated with a genetic algorithm, which aimed to minimize the location and speed error between simulated and actual trajectories, extracted from the video sequence through computer vision. Validation results showed that the model was capable of reproducing pedestrian trajectories with high accuracy in regard to average location and speed error. The average location error for 271 pedestrians considered in the validation was 0.49 m, while the average speed error was 0.04 m/s. Detailed analysis of crossing speed for both conventional and diagonal crossings was presented, and the ability of the model to produce the same speed distributions observed in actual data was confirmed. Furthermore, the ability of the model to reproduce five interactions that were frequently observed in the data was assessed. Results showed that the model was capable of reproducing the actual behavior taken by pedestrians during these interactions with high accuracy, from 80% to 100%.

Automated analysis of pedestrian walking behaviour at a signalised intersection in China

An analysis of pedestrian walking behavior using gait parameters is presented; it uses automated video analysis to collect pedestrian data at a signalized intersection in Nanjing, China. Two aspects of microscopic pedestrian behavior are considered: First, the walking mechanism represented by pedestrian gait parameters. Second, the non-conforming crossing behavior of pedestrians. The effect of various pedestrian related attributes are investigated. The results show high accuracy in automatically detecting pedestrian violations, with an 85.2% correct detection rate. The walking speed and gait parameters for spatial violators are found to be significantly higher compared to non-violators. It is also found that pedestrians who enter the crosswalk during the late stage of the green pedestrian phase often adopt higher walking speed. The gait analysis shows that males tend to have a higher walking speed, walk ratio and longer step length than females. Single pedestrians are found to have higher speed and step frequency compared to pedestrians in groups. The presence of bikes on crosswalks significantly decreases the pedestrian walking speed, step length and frequency, leading to more gait variability. Such results are useful for many future applications such as calibration of simulation models and violation detection.

Adaptive Walk Intervals

If the vehicular phase concurrent with a pedestrian phase is running under fully actuated control or is a noncoordinated phase under coordinated-actuated control, the length of its green is not known when the phase begins; it could run anywhere between a (known) minimum and maximum green, depending on when a gap is detected. In such a case, walk intervals are generally kept to a minimum length to prevent the pedestrian phase from constraining the ending of green that can lead to situations in which the pedestrian phase has cleared yet the concurrent phase continues its green for 20 more seconds. Proposed is the concept of an adaptive walk interval whose length is based on the predicted length of the concurrent phase’s green, which in turn is calculated cycle by cycle with data from recently past cycles. That way, during heavy traffic periods in which the vehicular phase usually goes well beyond its minimum, a longer-than-minimum walk interval can be provided with very little impact on signal operation or vehicular delay. Two methods, ratio estimation and stratification, are proposed and tested for predicting the green time needed by a vehicular phase; both methods use as data only traffic signal timing data from the last several cycles. Simulation tests with coordinated-actuated and fully actuated control, with and without pedestrian recall, and with and without permissive windows show that adaptive walk intervals can markedly reduce pedestrian delay with almost no impact on vehicular delay.

Investigating the applicability of exclusive pedestrian phase at two‐phase actuated controlled intersections

SummaryThe exclusive pedestrian phase (EPP) has been used in many countries to promote walking around downtown areas by increasing the ease and convenience of pedestrian crossing. However, its applicability has not been systematically demonstrated, especially when an intersection is operated in actuated mode. This paper presents an extensive simulation‐based analysis of the applicability of EPP as compared with a normal concurrent pedestrian‐phase pattern at an isolated intersection controlled by actuated logic. Actuated signal control logics for EPP‐actuated and conventional concurrent pedestrian phase‐actuated controls are developed. Both of these control logics consider pedestrian crossing demands and can adapt to changes in vehicle traffic to reduce vehicle delay as well. A simulation model of a two‐phase controlled intersection is built and calibrated based on field data using VISSIM (PTV Planung Transport Verkehr AG in Karlsruhe, Germany). Extensive analysis is conducted to reveal fully the applicable EPP domain in terms of vehicle traffic demand, pedestrian demand, vehicle turning ratio, and pedestrian diagonal crossing ratio. The results show that the performance and applicable domain of EPP are jointly determined by those five factors. EPP significantly outperforms concurrent pedestrian phase if the vehicle turning ratio is greater than 0.6 and the pedestrian diagonal crossing ratio is greater than 0.6. These results can help traffic engineers in choosing the appropriate pedestrian‐phase patterns at actuated signalized intersections. Copyright © 2015 John Wiley & Sons, Ltd.

Leveraging Signal Infrastructure for Nonmotorized Counts in a Statewide Program

Transportation agencies are beginning to explore and develop non-motorized counting programs. This paper presents the results of a pilot study that tested the use of existing signal infrastructure—Model 2070 signal controllers with advanced software to log pedestrian phase actuations and detections from bicycle lane inductive loops—to count pedestrians and bicycles. The pilot study was conducted at a typical suburban signalized intersection with heavy motorized traffic that was instrumented on all four approaches with pedestrian push buttons and advance inductive loops in the bicycle lane for signal operation. One day (24 h) of video data was collected as ground truth. The data were reduced and compared with the controller logs. Results indicated that using pedestrian phases as a proxy for estimating pedestrian activity was a promising avenue for counting programs. During the pilot study day, 596 pedestrians crossed the intersection, and 482 pedestrian phases were logged (i.e., 1.24 pedestrian crossings per phase logged). However, bicycle counts were not as accurate because of a number of site-specific factors: ( a) inductive loop location, ( b) loop sensitivity settings, ( c) loop shape, and ( d) nearly half of the cyclists passing through the intersection were riding on the sidewalk. The pilot study was part of a research project to develop guidelines for a statewide bicycle and pedestrian counting program for the Oregon Department of Transportation.

Optimization of pedestrian phase patterns and signal timings for isolated intersection

This paper establishes quantitative criteria for selecting pedestrian phase patterns between the exclusive pedestrian phase (EPP) and the normal two-way crossing (TWC) with both safety and efficiency factors traded-off in an economic evaluation framework. The safety effect is assessed by modeling the number of pedestrian-vehicle exposures and pedestrian violations (i.e., pedestrian noncompliance) based on the traffic conflict technique (TCT); and the operational efficiency is measured with a new model considering pedestrian delay due to signal, conflicts, and detour. Both safety and efficiency performance indices are converted to monetary values in an integrated model to simultaneously select pedestrian phase patterns and optimize signal timings of an intersection with two phases. Case study results have shown the promising property of the proposed approach to assist transportation professionals in properly selecting pedestrian phase patterns at signalized intersections.

Analysis on Pedestrian Speed at Signalized Intersections with Exclusive Pedestrian Phases

To analyze the pedestrian speed of at signalized intersections with exclusive pedestrian phases, data of pedestrian speed at 3 typical signalized intersections in Weihai were collected by video survey and artificial measurement and statistical analysis were conducted by SPSS. Influence factors including gender, different time and stage when pedestrian crossing the street. The 15th percentile speed of pedestrians crossing intersection was put forward which may provide theoretical base for the conformation of pedestrian green light of signalized intersections with exclusive pedestrian phases.

Red Light Running Behavior of Electric Bicycles at Signalized Intersections in China

A comparative analysis was conducted on the red light running behavior of the riders of scooter-style electric bicycles (e-scooters), bicycle-style electric bicycles (e-bikes), and bicycles as they crossed signalized intersections. The crossing behaviors of 5,646 riders (1,568 e-bikes, 2,612 e-scooters, and 1,466 bicycles) were observed. The average red light running rates for e-bikes, e-scooters, and bicycles at the selected sites were 24.9%, 25.0%, and 18.3%, respectively. The rates for e-bikes and e-scooters were significantly higher than those for bicycles. The difference in the rates between e-bikes and e-scooters was not statistically significant. A binary logit model was developed to evaluate how various factors affected the red light running rates of two-wheeled vehicles at signalized intersections. Results of a comparison of traffic conflicts caused by various red light running two-wheeled vehicles indicated that bicycles were slightly more likely to be involved in traffic conflicts than e-bikes or e-scooters as they crossed intersections during a red pedestrian phase. Also, e-bikes were less likely than e-scooters and bicycles to be involved in traffic conflicts in the middle stage of a red pedestrian phase. Both e-scooters and e-bikes had higher crossing speeds than bicycles. Although e-scooters traveled at speeds significantly higher than e-bikes did when crossing intersections during green phases, the difference in crossing speeds between red light running e-bikes and red light running e-scooters was not statistically significant.

Understanding Pedestrian and Bicyclist Compliance and Safety Impacts of Walk Modes at Signalized Intersections for a Livable Community

With increasing energy costs as well as rampant congestion in major U.S. cities, the popularity of walk and bike mode choices has increased in recent years. NHTSA has estimated that, in 2011, 11.1% of pedestrian fatalities and 18.5% of bicyclist fatalities in the United States occurred in Florida, although the state accounted for just 6.1% of the nation's population. In addition, intersections are hot spots for vehicle–pedestrian conflicts. This finding has been confirmed by FHWA's estimate that in the United States nearly one in five pedestrian fatalities occurs at an intersection. Because signalized and nonsignalized intersections are conflict points for vehicles, pedestrians, and bicyclists, traffic control methods to ensure that safety is not compromised are essential. For the examination of the safety effects of walk modes at signalized intersections, four locations in the Tampa Bay area were chosen. Two of the locations operated with rest in walk and pedestrian recall, and the other two operated without rest in walk and pedestrian recall. The study collected a total of 26 h of data in early 2013 at the four study sites, with a yield of 202 pedestrian and bicyclist observations. The behaviors were modeled with a multinomial logit model. The modeling found that the presence of rest in walk and pedestrian recall on minor street pedestrian phases, which operated concurrently with major street vehicle phases, encouraged higher pedestrian and bicyclist compliance rates. The presence or absence of the combination of rest in walk and pedestrian recall was found to be the most influential variable examined.

APPRAISAL OF AIRPORT ROUNDABOUT ON THE ANTOA ROAD, KUMASI-GHANA USING MICRO SIMULATION MODEL

Roundabouts have become increasingly popular in rec ent years as an innovative operational and safety s olution at both low volume and high volume intersections. Roundabouts have a nof advantages over traffic signals depending on the conditions. They reduce the severity of crashes since head-on and ri ght-angle conflicts are nearly eliminated. They red uce through traffic speeds to provide a “calmer” roadway environment. This study appraised Airport roundabout on the Antoa Road in K umasi, Ghana using micro simulation model. Traffic and geometric data were collected on the field. The analysis revealed that Airport roundabout was operating at a level of service F, which represente d worst conditions. Signalized intersection with 4 approach lanes on the two principal arterials was proposed to control all the movements. Exclusive pedestrian phases were prop osed to protect pedestrians.

Optimization of pedestrian phase patterns at signalized intersections: a multi‐objective approach

SUMMARYThis paper presents a multi‐objective optimization model and its solution algorithm for optimization of pedestrian phase patterns, including the exclusive pedestrian phase (EPP) and the conventional two‐way crossing (TWC) at an intersection. The proposed model will determine the optimal pedestrian phase pattern and the corresponding signal timings at an intersection to best accommodate both vehicular traffic and pedestrian movements. The proposed model is unique with respect to the following three critical features: (1) proposing an unbiased performance index for comparison of EPP and TWC by explicitly modeling the pedestrian delay under the control of TWC and EPP; (2) developing a multi‐objective model to maximize the utilization of the available green time by vehicular traffic and pedestrian under both EPP or TWC; and (3) designing a genetic algorithm based heuristic algorithm to solve the model. Case study and sensitivity analysis results have shown the promising property of the proposed model to assist traffic practitioners, researchers, and authorities in properly selecting pedestrian phase patterns at signalized intersections. Copyright © 2013 John Wiley & Sons, Ltd.