Robert E. Novak

Audible pedestrian traffic signals: Part 1. Prevalence and impact

A collaborative project between the San Diego Association of Governments and San Diego State University (5) evaluated the effectiveness of audible pedestrian traffic signals in aiding visually disabled and elderly persons to walk in their community with greater safety. Three aspects of audible pedestrian traffic signals were investigated: 1) the patterns of use and the impact of these signals on pedestrian traffic safety; 2) the physical characteristics of the sound emitted by the devices; and, 3) the detection of the emitted sounds in the presence of various traffic noise levels. This paper reports on the prevalence and impact of audible traffic signals were ascertained through seeking information from traffic engineers in 71 North American cities; soliciting opinions about these signals from various school officials, social agencies, and volunteer organizations that serve persons with vision impairments; and analyzing pedestrian accident rates at intersections before and after the installation of such signals. The other two aspects of the project are reported in accompanying articles (6,7) that appear in this issue of the Journal of Rehabilitation Research and Development.

Audible pedestrian traffic signals: Part 2. Analysis of sounds emitted

This project evaluated audible pedestrian traffic signals from three perspectives: 1) the patterns of use and the impact of these signals on pedestrian travel; 2) the physical characteristics of the sound emitted by these devices; and, 3) the detection of their emitted sounds in the presence of various traffic noise levels. This paper, the second of three companion articles (2, 3), examines the sounds emitted by the Nagoya/Traconex audible traffic signal, the unit most commonly found in the western United States and almost exclusively in California. The sounds emitted by the north-south and east-west Traconex audible signals were analyzed for their loudness, directionality, frequency spectrum, and temporal characteristics using standard engineering tools including an anechoic chamber, sound level meters, spectrum analyzers, and signal analyzers.

Equipotentiality of function in dichotic listening

Listeners who had demonstrated right-ear dichotic listening preference in the first of four listening sessions were randomly assigned to an experimental and control group. Both groups participated in three more dichotic listening sessions. For sessions 2 and 3, left-ear responses were reinforced for the experimental group listeners. There was a significant interaction between groups and sessions. After a drop to equal numbers of right- and left-ear responses in session 2, the control group demonstrated significant right-ear preference in sessions 3 and 4. The responses of the experimental group showed strong left-ear preferences in sessions 2 and 3. Their left-ear gains were preserved in session 4, while their right-ear responses returned to the level demonstrated in session 1. It was concluded that the experimental group had learned to attend to and report left-ear stimuli without loss of right-ear report competence. Within the experimental paradigm, equipotentiality of function has been demonstrated.