Good qualities we identified in a discussion: - directional - many short duration rather than continuous - sonorous (melodic or consonant) - amplitude appro

Good qualities we identified in a discussion: - directional - many short duration rather than continuous - sonorous (melodic or consonant) - amplitude appropriate to time of day and danger A big mistake we make is confusing "attention", "arresting" and "annoying" qualities. Dissonant sounds seem like they grab your "attention" quicker, but that's not necessarily true, it's really about the spectrum morphology in the first 100ms - those sounds (like bells) have better localisation qualities - they tend to elicit an orientation response and have better front-rear ambiguity so we can position them better. Knowing where an emergency vehicle is, is as important as just knowing it's there. From video evidence of interchanges and roundabouts what we see is that the sound of sustained sweep sirens often creates chaos, with drivers panicking, pulling on to pavements or making other rash and dangerous sudden manoeuvres.