Intersections and signals have become more complex and it is important that Orientation and Mobility (O&M) Specialists and blind travelers understand these changes for safe travel. Skills and strategies used by pedestrians who are blind or visually impaired to cross streets at signalized intersections were developed at intersections that had pretimed signals, which meant the signal changed on a regular basis. Signalization has also become more complex, with the introduction of vehicular and pedestrian actuation and multiple phases. This increased complexity has made some previously accessible intersections now inaccessible for pedestrians with visual impairments.
It is essential for O&M Specialists to understand these changes so that they are incorporated into their curriculum and so that these specialists can adapt their instructional techniques and advocate for their consumers' needs.
This chapter gives an overview of the decisions, design, and terms that are used by traffic engineers as they design and install traffic signals.