Warning Tone Selection for a Reverse Parking Aid System

Two studies were conducted to identify characteristics of a preferred warning signal for a Reverse Parking Aid System. In the first study, twenty participants rated the perceived urgency of 6 warning tone pulse rates ranging from 1 to 8 Hz and a solid tone. The results indicated a strong differentiation of perceived urgency between the 1 Hz, 2 Hz, 4 Hz, and 6 Hz pulse rates. The majority of participants perceived the 6 Hz and higher rates as very urgent. The second study examined 6 tone frequencies ranging from 500 Hz–1500 Hz. Twenty-five participants performed reverse parking maneuvers using each of the six tones. The 750 Hz and 1000 Hz tones were rated well both with and without the radio playing, and were therefore recommended.