Rea Mark S, Bullough John D
Lighting Research Center, Rensselaer Polytechnic Institute, 21 Union Street, Troy, NY 12180 USA.
Transp Res Part F Traffic Psychol Behav. 2016 Nov;43:36-47. doi: 10.1016/j.trf.2016.09.018.
Yellow flashing warning beacons help protect front line service workers, including those in transportation, utility and construction sectors. To safeguard these workers, beacons should be readily detected and should provide veridical information about their relative movement. Two psychophysical laboratory experiments were conducted to provide empirical foundations for two aspects of warning beacon performance, detection and judgments of relative movement. In the first experiment reaction times were measured to the onset of flashing warning beacons varying in peak intensity while observers viewed different scene conditions. Observers also judged the visibility of nearby low-contrast targets in the presence of the flashing warning beacons. Asymptotic response times to the onset of beacons occurred when their peak intensity was at least 750 cd during daytime. Visibility of low contrast targets during nighttime, when glare is most critical, did not decrease substantially when the peak intensity was below 2000 cd. In the second experiment response times were measured to warning beacons of different flash-sequence patterns as they approached the observer. Judgments of gap closure were improved, relative to fully-on/fully-off flashing, with flash sequences where the minimum beacon intensity was at least 10% of the peak intensity and with two synchronized flashing beacons rather than one. With regard to performance specifications, the minimum value for the peak intensity of warning beacons should be 750 cd, with a maximum value of 2000 cd for detection. Fully-on/fully-off flash sequences should be changed to fully-on/partial-off to enhance judgments of gap closure on moving vehicles. Moreover, two flashing warning beacons, rather than one, should be mounted on service vehicles to improve gap closure judgments.
黄色闪烁警示信标有助于保护一线服务人员，包括运输、公用事业和建筑行业的人员。为了保护这些人员，信标应易于被察觉，并应提供有关其相对运动的真实信息。进行了两项心理物理学实验室实验，为警示信标性能的两个方面，即检测和相对运动判断，提供实证依据。在第一个实验中，当观察者观看不同场景条件时，测量了对峰值强度不同的闪烁警示信标开始出现时的反应时间。观察者还判断了在闪烁警示信标存在的情况下附近低对比度目标的可见性。当信标的峰值强度在白天至少为750坎德拉时，对信标开始出现的渐近反应时间出现。在夜间，当眩光最为关键时，当峰值强度低于2000坎德拉时，低对比度目标的可见性并没有大幅下降。在第二个实验中，测量了不同闪光序列模式的警示信标接近观察者时的反应时间。相对于全亮/全灭闪烁，当最小信标强度至少为峰值强度的10%且有两个同步闪烁信标而非一个时，间隙闭合的判断得到了改善。关于性能规格，警示信标的峰值强度最小值应为750坎德拉，用于检测的最大值为2000坎德拉。全亮/全灭闪光序列应改为全亮/部分熄灭，以增强对行驶车辆间隙闭合的判断。此外，服务车辆上应安装两个闪烁警示信标而非一个，以改善间隙闭合判断。
