Pedestrian perception-based level-of-service model at signalized intersection crosswalks

"jats:p"Pedestrian level of service (PLOS) is an important measure of performance in the analysis of existing pedestrian crosswalk conditions. Many researchers have developed PLOS models based on pedestrian delay, turning vehicle effect, etc., using the conventional regression method. However, these factors may not effectively reflect the pedestrians’ perception of safety while crossing the crosswalk. The conventional regression method has failed to estimate accurate PLOS because of the primary assumption of an arbitrary probability distribution and vagueness in the input data. Moreover, PLOS categories in existing studies are based on rigid threshold values and the boundaries that are not well defined. Therefore, it is an important attempt to develop a PLOS model with respect to pedestrian safety, convenience, and efficiency at signalized intersections. For this purpose, a video-graphic and user perception surveys were conducted at selected nine signalized intersections in Mumbai, India. The data such as pedestrian, traffic, and geometric characteristics were extracted, and significant variables were identified using Pearson correlation analysis. A consistent and statistically calibrated PLOS model was developed using fuzzy linear regression analysis. PLOS was categorized into six levels ("jats:italic"A"/jats:italic"–"jats:italic"F"/jats:italic") based on the predicted user perception score, and threshold values for each level were estimated using the fuzzy "jats:italic"c"/jats:italic"-means clustering technique. The developed PLOS model and threshold values were validated with the field-observed data. Statistical performance tests were conducted and the results provided more accurate and reliable solutions. In conclusion, this study provides a feasible alternative to measure pedestrian perception-based level of service at signalized intersections. The developed PLOS model and threshold values would be useful for planning and designing pedestrian facilities and also in evaluating and improving the existing conditions of pedestrian facilities at signalized intersections. Document type: Articl

Pedestrian Crossing Treatment Warrants for Midblock Crosswalks Under Mixed Traffic Conditions

Pedestrian crossings are important for accessing the adjacent land use facilities in daily life. Improperly designed crossing facilities cause discomfort to pedestrians and may even jeopardize their safety as well as being a hindrance to the smooth flow of vehicle traffic. These problems exist especially in developing countries such as India, where mixed traffic conditions prevail and road discipline is essentially absent. Thus, the design of efficient crossing facilities considering the flow of both pedestrians and vehicles is of utmost importance in these countries. In this regard, the objective of the current study was to propose warrants for pedestrian crossing facilities in midblock sections under mixed traffic conditions. To achieve this objective, pedestrian-vehicle (PV2) conflict analysis was carried out at eight different unprotected mid block crosswalks in Mumbai, India. Videographic surveys were conducted and vehicle and pedestrian volumes were extracted, along with pedestrian-crossing characteristics such as crossing difficulty, safety and traffic, and vehicle characteristics. The initial computed PV2-values were adjusted by different factors, and k-means cluster analysis was carried out to determine the threshold PV2-values for selection of a suitable crosswalk facility. The study also highlighted the importance of taking into consideration site characteristics for evaluation of a mid block crosswalk facility. The results of this study are expected to have a wide range of applications in the design of new crosswalk facilities or in the improvement of existing pedestrian crosswalk facilities under mixed traffic conditions

PEDESTRIAN QUALITY OF SERVICE AT UNPROTECTED MID-BLOCK CROSSWALK LOCATIONS UNDER MIXED TRAFFIC CONDITIONS: TOWARDS QUANTITATIVE APPROACH

Safety, comfort, convenience and minimal delay are essential for pedestrians at mid-block crosswalk locations. Therefore, it is necessary to evaluate the quality of crosswalk with these qualitative parameters. In this study, qualitative parameters such as safety, crossing opportunities (available time gaps) and delay index values are considered as a single measure of effectiveness as a Pedestrian Crossing Index (PCI) for evaluation of Quality Of Service (QOS) at unprotected mid-block crosswalk locations under mixed traffic conditions. Further, the study is aimed at identifying the factors contributing to the pedestrian QOS. In order to achieve these objectives, field surveys were conducted at eight different unprotected mid-block crosswalk locations to collect pedestrian individual (age and gender), behavioural, traffic and roadway characteristics. An ordered probit model has been developed to find out the significant factors contributing to the pedestrian QOS by taking QOS as the dependent variable and other collected variables as independent variables. The model results show that several factors have significant effect on pedestrian QOS and out of these, factors such as rolling behaviour, speed change behaviour of pedestrian, vehicle speed, number of lanes and number of vehicle encountered were identified as the primary factors affecting pedestrian QOS at unprotected mid-block crosswalk locations. The developed model may be useful for design and evaluation of the existing pedestrian QOS at unprotected mid-block crosswalk locations under mixed traffic conditions

Study of the impact of exclusive bus lane under highly heterogeneous traffic condition

The objective of this paper is to study and quantify the possible impact of provision of exclusive bus lane under heterogeneous traffic condition. The quantum of increase in level of service of bus due to introduction of exclusive bus lane was determined using a simulation model of heterogeneous traffic flow. The impact of introduction of an exclusive bus lane is measured in terms of reduction in speed of other categories of motor vehicles, due to the consequent reduction in road space, over a wide range of traffic volume. The main finding of the simulation experiment is the quantification of the maximum permissible volume to capacity ratio that will ensure a level of service of C for the traffic stream comprising all the motor vehicles, except the buses, on a typical six-lane and eight-lane divided urban roads. This study is also concerned with estimation of the probable shift of the personal vehicle users to bus due to provision of exclusive bus lanes

Evaluation of pedestrian crosswalk level of service (LOS) in perspective of type of land-use

In India pedestrians usually cross the road at mid-block crosswalks due to ease of access to their destination or the development of adjacent land use types such as shopping, business areas, school and residential areas. The behaviour of pedestrian will change with respect to different land use type and this change in behaviour of pedestrian further reflects change in perceived level of service (LOS). So, it is important to evaluate the quality of service of such crossing facilities with respect to different land-use type under mixed traffic conditions. In this framework, pedestrian perceived LOS were collected with respect to different land-use type such as shopping, residential and business areas. The ordered probit (OP) model was developed by using NLOGIT software package, with number of vehicles encountered, road crossing difficulty as well as safety considered as primary factors along with pedestrian individual factors (gender and age), land-use type and roadway geometry. From the model results, it has been concluded that perceived safety, crossing difficulty, land-use condition, number of vehicles encountered, median width and number of lanes have significant effect on pedestrian perceived LOS at unprotected (un-signalized) mid-block crosswalks in mixed traffic scenario. The inferences of these results highlights the importance of land use planning in designing a new set of pedestrian access facilities for unprotected mid-block crosswalks under mixed traffic conditions. Also the study results would be useful for evaluating pedestrian accessibility taking into account different land-use type and planning required degree of segregation with vehicular movement at unprotected mid-block crosswalk locations. (C) 2015 Elsevier Ltd. All rights reserved

Proactive pedestrian safety evaluation at unprotected mid-block crosswalk locations under mixed traffic conditions

The pedestrian safety can be evaluated by proactive methods (conflict techniques). Proactive method is a cost-effective technique as compared to the historic crash data analysis. Pedestrian safety studies at mid block crosswalks based on proactive methods are required due to the growing number of pedestrian crossing facilities in developing countries. Hence, the present study evaluated the pedestrian safety at unprotected mid-block crosswalks by considering the proactive safety measure as a pedestrian safety margin (PSM). PSM is the time difference between accepted vehicular time gap with reference to the pedestrian crossing path and pedestrian actual crossing time (based on the field conditions). To fulfill this objective eight unprotected mid-block crosswalks were selected which have different roadway characteristics. Video graphic survey has been conducted for data collection at these locations. PSM values were extracted corresponding to the pedestrian behavioural, vehicular and traffic characteristics at all the eight crosswalks. Further, stepwise regression and binary logit models (the probability of pedestrian-vehicle non-conflict) have been developed in order to find out the factors contributing to the PSM values as well as predicting the probability of avoiding conflict with an approaching vehicle at unprotected mid-block crosswalks. From the study, it is observed that pedestrian behavioural characteristics such as rolling behaviour and speed change conditions significantly reduce the PSM values, and it influences the probability of avoiding conflict with an approaching vehicle at unprotected mid-block crosswalks. These findings may be useful for evaluation of the existing unprotected mid-block crosswalk locations and for increasing the pedestrian safety at these crosswalks by considering suitable control measurements on pedestrian behaviour under mixed traffic conditions. (C) 2016 Elsevier Ltd. All rights reserved

A NEW APPROACH TO ESTIMATE PEDESTRIAN DELAY AT SIGNALIZED INTERSECTIONS

Enhancing pedestrian safety and improving the design standards of pedestrian facilities at signalized intersection requires a clear understanding of pedestrian delay model and pedestrian crossing behaviours under mixed traffic condition. The existing delay models do not consider the behavioural constrains of pedestrians. This research has been undertaken with the aim of developing a suitable pedestrian delay model for signalized intersection crosswalks, based on considering actual pedestrian crossing behaviours. The required model parameters were extracted from the video-graphic survey conducted for the selected four signalized intersections in Mumbai (India). Crossing behaviours of pedestrians were examined through field data in terms of pedestrian arrival pattern, crossing speed, compliance behaviour and pedestrian-vehicular interactions. Based on pedestrian crossing behaviour analysis results, two new pedestrian delay estimation models were developed and the models were validated by comparing with field and existing model values. The performance level of the proposed models is showing more precise and reliable solutions. The first pedestrian delay model is developed on the basis of compliance behaviour, has two components, such as waiting time delay and crossing time delay. This model can be used to evaluate pedestrian Level Of Service (LOS) and signal timing optimization. The second developed pedestrian delay model is based on noncompliance behaviour, has three components, such as waiting time delay, crossing time delay, and pedestrian-vehicular interaction delay. This model can also be used to evaluate the quality of pedestrian flow, estimating accurate pedestrian delay and LOS for local conditions, which is representative of the prevailing pedestrian condition

Proactive safety evaluation of a multilane unsignalized intersection using surrogate measures

Road traffic safety is emerging as an area of increased attention and concern in many countries including India. Safety evaluation by conflict study using surrogate measures is a proactive method which does not require any accident data. Conflict study may be carried out using post encroachment time (PET) as a surrogate measure, where critical conflicts are determined based on certain threshold value of PET. Identifying critical conflicts using a threshold value of PET is good and correct for highways and major roads where traffic follows posted speed, but on highways with mixed traffic for varied speeds this is not correct. It can be seen that conflicts with PET less than the threshold value may not be critical if the speed of conflicting vehicle is less. Similarly, conflicts with PET more than threshold value may also be critical if the speed of conflicting vehicle is high. The speed of conflicting vehicle is also important in evaluating severity of conflict. Hence, the use of PET alone for conflict study is not correct for evaluating safety of intersections on highways where traffic follows varied speeds. Therefore, in the present study, safety evaluation of an unsignalized intersection is carried out using two surrogate measures, PET and the speed of corresponding conflicting through vehicle. A term critical speed is proposed to identify critical conflicts. Critical speed for a particular PET value is determined using stopping/braking distance concept. Results show that there are significant percent of conflicts which are critical at the intersection. This shows that drivers of right-turning vehicles do take risks in accepting small gaps in through traffic at the intersection, which is dangerous. As crossing maneuver depends on length and speed of turning vehicle, the effect of type of turning vehicle has also been studied. Results show that right-turning light motor vehicles are at higher risk compared to two wheelers and heavy vehicles at the intersection. Safety evaluation of such unsignalized intersections may be carried out using this concept

Review of Pedestrian Level of Service Perspective in Developing Countries

Analyses of pedestrian-related issues have been gaining much attention from researchers in recent years, particularly studies of pedestrian safety and pedestrian level of service (LOS) in developing countries. The focus for evaluating pedestrian LOS has shifted from quantitative methods to qualitative methods and factors to be considered have been changing. Crosswalks (namely, signalized, unsignalized, and midblock) are complex locations because of the interaction of pedestrians with the vehicle flow. Pedestrian LOS at crosswalks is quite different from that on sidewalks. A measure of effectiveness (MOE) is usually adopted for evaluation of pedestrian facilities, and the MOE changes with the type of facility. Pedestrian delay and space at the corner are considered as MOEs for signalized intersections. The MOE might depend on pedestrian safety, delay, available vehicle gaps (crossing difficulty), and behavior of pedestrians as well as that of vehicle drivers at unprotected midblock crosswalks. This study sought to identify the importance of pedestrian LOS in the context of developing countries, particularly at unprotected midblock crosswalks. To achieve this objective, a review of the literature was carried out on the pedestrian LOS at various facilities such as the sidewalk, intersection, and midblock crosswalk. The review highlighted the need for further pedestrian LOS studies at various facilities under mixed traffic

Evaluation of Pedestrian-Vehicle Conflict Severity at Unprotected Midblock Crosswalks in India

Promoting and creating proper facilities for nonmotorized (pedestrian and bicycle) trips is very important in an urban transportation system to enhance pedestrian safety. Pedestrian-vehicle conflicts on urban roads are increasing, particularly at road crossings, because of the tremendous rate of growth in vehicle traffic in developing countries. Accident statistics clearly indicate the need to improve pedestrian safety and to analyze the pedestrian-vehicle interactions and collisions more deeply. This study analyzed the severity of pedestrian-vehicle conflicts at unprotected midblock crosswalk locations under mixed traffic conditions. The pedestrian-vehicle conflicts were considered on the basis of a pedestrian safety margin, which can be defined as the time difference between the time gap of an approaching vehicle and the pedestrian crossing time. For this purpose, field surveys were conducted at eight unprotected midblock crosswalk locations. Data such as pedestrian demographics and behavioral, traffic, vehicle, and roadway characteristics were considered to analyze the severity of the pedestrian-vehicle conflicts. The study identified the significant contributing factors in such conflicts by using an ordered probit model. The model's results show that rolling behavior, pedestrian speed change condition, land use type, and vehicle speed have a significant effect on the severity of pedestrian-vehicle conflicts. The findings of this study contribute to developing traffic countermeasures to reduce the severity of pedestrian-vehicle conflict levels in order to improve pedestrian safety at unprotected midblock crosswalk locations under mixed traffic conditions. More studies at various unprotected midblock crosswalk locations would be useful to develop guidelines for redesigning the existing midblock crosswalk facilities by introducing suitable traffic control measures