Experimental observations on the optimal layout of orientation blocks for safe road crossing by the visually impaired

- The reliability of road crossing facilities for the visually impaired varies greatly.
- The authors propose the use of “orientation blocks” installed at crosswalk entrances.
- An experiment was conducted to objectively evaluate walking trajectories.
- Sensory evaluations by participants in the experiment were also analyzed.
- An optimal manner of laying the blocks to maximize their effectiveness was derived.

For people with visual impairments who face difficulties when crossing the road, in urban areas of Japan the infrastructure designed to provide an indication of crossing direction and the curbstones at sidewalk-roadway boundaries often varies in reliability from one crossing to another. If anything, this promotes stress for users and is an issue for which improvement is urgently needed. The authors have proposed new orientation blocks to be installed at crosswalk entrances as a means of more accurately indicating to people with visual impairments the trajectory to follow when crossing the road, and in prior research have derived desirable specifications for the profile of these blocks and their position relative to tactile walking surface indicators (TWSI).For this paper, in order to examine in greater detail the desirable position of orientation blocks relative to TWSI, the authors conducted an experiment using totally blind subjects to evaluate conditions on a 10 m walk that simulated an actual crossing. The results, based on observations of the trajectories walked by participants in the experiment and interviews eliciting their subjective evaluations, showed that separating orientation blocks and blister tactile blocks by about 8-12 cm is effective in constraining lateral deviation at a point 5 m from the start of crossing and that an 8 cm separation was desirable in order to maintain an effective reduction of mental stress while crossing.