Street-Crossing Decision Making in Low Vision

描述(申请人提供)：过马路是一项复杂、困难和危险的任务。在作出过街决定时，行人必须预留一个较佳的安全裕度，并判断车辆交通的缺口是否超过过马路所需的时间。以前的过马路研究表明，老年人、视障人士和盲人行人在过马路时会做出不安全的决定。本研究将评估这些高危行人群体的过街决策绩效。我们将使用一种创新的无标准度量来评估行人判断的准确性和可靠性 至于车辆空档时间是否足够让他们横过马路。这个 行人的首选安全裕度将不包括在这一交叉路口决定中。我们亦会量度每名行人的横过马路准则，以确定每名行人首次认为可以安全横过马路的间隔时间。行人的安全裕度将包括在这一交叉路口决定中。收集的数据将解决四个目标。 目标1将评估作为视觉(视力、对比敏感度和视野)以及行人的特征(年龄和步行速度)的函数的过街决策性能如何变化。如果行人在作出过街决定时，没有补偿他们的感官和动作限制，我们预计他们的准确性和/或可靠性会相应下降，过马路的标准也会缩短。如果行人弥补自己的局限性，采取保守或谨慎的过马路策略，就会发现相反的情况。目标2将比较自称过街有困难的视障和盲人行人与自称没有过街困难的视障和失明行人之间的准确性、可靠性和横过马路的标准。如果过街决策绩效与行人的自信心有关，那么那些自我报告遇到困难的行人就会表现出不安全的过马路决策。没有困难的行人会表现出安全的过马路决定。目的3验证当前定向和机动性(O&M)街道交叉路口决策训练方案训练后，行人的准确性、可靠性和过街标准是否有所改善。目标4将比较在三种不同类型的十字路口环境下测量的行人过马路的准确性、可靠性和标准。在不同的环境中，一致的过马路决策行为表明，这项研究的发现是可以推广的。不一致的决策行为将提供信息，并值得进一步调查。总而言之，该项目的发现将提供对影响过马路决策绩效的因素的更详细的了解。他们还将指导为低视力(LV)康复专家制定客观的循证建议，建议他们何时应转介患者进行过街决策培训。 与公共卫生相关：人口中视力低下的发生率不断增加，这导致人们加大努力，通过专门的定向和机动性(O&M)培训来改善行人的安全过马路决策。运用各种量化指标，对视障、盲人和老年行人在真实的室外交通环境中的过街决策绩效进行评估。通过这些测量，我们将确定过马路决策培训是否可以改善视障和盲人的安全，以及受试者的特征、视觉功能、对自己能力的感知以及过马路环境的特征是否影响他们做出过马路决策的能力。

DESCRIPTION (provided by applicant): Crossing the street is a complex, difficult and dangerous task. When making street-crossing decisions, pedestrians must allow for a preferred safety margin and judge whether the gap in vehicular traffic exceeds the time needed to cross the street. Previous street-crossing research has shown that the elderly, visually impaired, and blind pedestrians make unsafe street-crossing decisions. This study will evaluate the street-crossing decision making performance of these high-risk pedestrian groups. We will use an innovative criterion-free metric to evaluate the accuracy and reliability of pedestrians' judgments on whether the vehicular gap time is of sufficient duration to allow them to cross the street. The pedestrian's preferred safety margin will not be included in this crossing decision. We will also measure each pedestrian's criterion for crossing by determining the gap time when each pedestrian first thinks that it is safe to cross. The pedestrian's safety margin in this crossing decision will be included. The collected data will address four aims. Aim 1 will assess how street-crossing decision making performance changes as a function of vision (visual acuity, contrast sensitivity and visual fields), and a pedestrian's characteristics (age and walking speed). If pedestrians do not compensate for their sensory and motor limitations when making their street-crossing decisions, we expect to see a corresponding decrease in their accuracy and/or reliability and a shortened criterion for crossing. If pedestrians compensate for their limitations and adopt a conservative or cautious street-crossing strategy the converse will be found. Aim 2 will compare the accuracy, reliability and criterion for crossing between visually impaired and blind pedestrians who self-report having difficulty crossing the street and those who self-report having no difficulty. If street-crossing decision making performance is related to a pedestrian's self-confidence, those pedestrians who self-report having difficulty would exhibit unsafe street-crossing decisions. Pedestrians who have no difficulty would exhibit safe street-crossing decisions. Aim 3 will test the hypothesis whether pedestrian accuracy, reliability and the criterion for crossing improves after training with a current Orientation and Mobility (O&M) street-crossing decision training program. Aim 4 will compare the accuracy, reliability and criterion for crossing in pedestrians measured at three different types of crossing environments. Consistent street-crossing decision making behavior across different environments would suggest that the study's findings are generalizable. Inconsistent decision behavior would be informative and warrant further investigation. Collectively, the project's findings will provide a more detailed understanding of the factors that affect street-crossing decision making performance. They will also guide the development of objective evidence-based recommendations for low vision (LV) rehabilitation specialists about when they should refer patients for street-crossing decision training. PUBLIC HEALTH RELEVANCE: The increasing incidence in low vision in the population is resulting in increased efforts to improve pedestrian safety through specialized orientation and mobility (O&M) training in street-crossing decision making. Using various quantitative measures, we will evaluate the street-crossing decision making performance of visually impaired, blind and elderly pedestrians in real, outdoor traffic environments. From these measurements, we shall determine whether street-crossing decision training can improve the safety of visually impaired and blind people and whether a subject's characteristics, vision functions, perception of their own ability, and the characteristics of the crossing environment affect their ability to make street-crossing decisions.