Time-space analysis is a new method for evaluating pedestrian activity spaces. This technique has been used in the Highway Capacity Manual (HCM) to determine pedestrian levels of service in corners and crosswalks. Although the new method follows established pedestrian traffic relationships, it had not been validated as a measure of actual street conditions. Evaluation of the pedestrian traffic impacts through the use of the HCM is a part of New York City's environmental review process for new developments, motivating the City Planning Commission, with U.S. Department of Transportation support, to sponsor a time-lapse photography study to validate the HCM pedestrian analysis method. Based on the analysis of time-lapse photography of pedestrian traffic activity at four Manhattan central business district intersections, the HCM time-space analysis model was found to be a valid procedure for determining pedestrian levels of service in corners and crosswalks. However, the photographic observations of pedestrian activity, combined with a computer sensitivity analysis of HCM model input parameters, indicated the following changes would improve the accuracy of the method: (a) standing area in corners for those waiting to cross increased from the HCM value of 5 sq ft/person to 7 sq ft/person; (b) occupancy time in corners for those moving through the corner changed from a uniform 4 sec to a value determined by a linear regression equation based on sidewalk width; (c) start-up time or delay of 3 sec for pedestrians to begin crossing in the HCM model eliminated to simplify the analysis model; and (d) walking speeds of pedestrians in crosswalks reduced from 4.5 ft/sec to 3.3 ft/sec as more representative of observed crosswalk platoon flow. An additional observation of the study was that although pedestrian levels of service show relatively little degradation because of turning vehicles, heavy pedestrian traffic noticeably reduced intersection capacity, potentially warranting turn restrictions where there are high crossing-volumes to increase intersection capacity, with secondary benefits of improved pedestrian safety and convenience.
Abstract In theory, mobile phone use may have beneficial and harmful effects. Individuals may use mobile phones to call for help or report various dangers and emergencies, but they may also go places they would not normally go without the phone. To test the perceptions of safety and subsequent behavior associated with mobile phone use, we conducted two surveys. One survey of 317 undergraduates at The Ohio State University (OSU) found that most students reported having a mobile phone and feeling that it made them feel safer at night. A follow‐up survey of 305 undergraduates at OSU found that about 40% of students with mobile phones stated that, with a mobile phone, they walked where they normally would not. However, smaller percentages said they used their mobile phones to call for help either in a crime or non‐crime situation or to report an accident, a crime, a reckless driver or a hazardous situation. The results suggest favorable and unfavorable outcomes associated with the mobile phone. Although using it to call for help from a threat, crime, or to report other unsafe conditions has value, the increased perceived safety associated with it may lead students to engage in risky behavior that could increase their chances of becoming a victim. Future work should consider whether mobile phone use increases or decreases the likelihood of victimization and of catching a predator. Résumé En théorie, utiliser un téléphone portable peut avoir des effets positifs et négatifs. Les individus peuvent s'en servir pour appeler de l'aide ou signaler divers dangers et urgences, mais ils peuvent aussi aller là où ils n'iraient pas normalement sans leur portable. Pour tester les sentiments de sécurité et le comportement subséquent associéà l'utilisation du téléphone portable, nous avons réalisé deux études. L'une, sur 317 étudiants de 1 er cycle de la Ohio State University (OSU), a montré que la plupart des étudiants disaient disposer d'un portable et avoir la sensation, grâce à lui, d'être plus en sécurité la nuit. D'après une enquête complémentaire sur 305 étudiants de 1 er cycle à OSU, environ 40 % des étudiants ayant un portable ont déclaré que, avec celui‐ci, ils se déplaçaient à pied dans des lieux où ils ne le feraient pas normalement. En revanche, une part plus restreinte a indiqué avoir utilisé son portable pour appeler de l'aide, que ce soit lors d'un crime ou non, ou bien pour signaler un accident, un crime, un conducteur imprudent ou une situation dangereuse. Les résultats suggèrent des conséquences favorables et néfastes dérivées du téléphone portable. Bien que son utilisation pour appeler de l'aide en cas de menace ou de crime, ou bien pour signaler d'autres risques, soit valable, la perception de sécurité renforcée qui lui est associée est susceptible d'entraîner les étudiants à avoir un comportement à risque, accroissant leur probabilité de devenir une victime. Un travail ultérieur devrait étudier si l'usage du téléphone portable accroît ou diminue la probabilité de victimisation et de capture d'un délinquant.
