JVIB, Copyright 2009 American Foundation for the Blind. All rights reserved.

Figure 1.
Average safety margin, by ambient sound level, in each condition. Click here for description

see description below Description: The figure is two stacked line graphs. The top graph represents three sound conditions: Straight, severe bend, and hill; the bottom graph also represents three sound conditions: baffle, minor bend, and trees. For both graphs, the x-axis represents Ambient sound level, (dBA) and has 6 values, from left to right: 35, 40, 45, 50, 55, and 60. The y-axes represent Safety margin (sec) and have 10 values, from bottom to top: -6, -4, -2, 0, 2, 4, 5, 8, 10, and 12.

Sound condition: Straight
Sound level, 3540; Safety margin: 7 - 8 - 11 - 7 - 8
Sound level, 4045; Safety margin: 8 7 - 6 - 5 - 4
Sound level, 4550; Safety margin: 4 - 3 - 6 - 1 1
Sound level, 5055; Safety margin: 1 negative 3 - 0 - negative 3 - negative 2
Sound level, 5560; Safety margin: --

Sound condition: Severe bend
Sound level, 3840; Safety margin: 1 negative 1 - 0
Sound level, 4045; Safety margin: 0 - 4 2 - negative 2 - 1
Sound level, 4550; Safety margin: 1 - 0 negative 4 - 0 - negative 2 - 0
Sound level, 5055; Safety margin: 0 - negative 4 - negative 5 - negative 3 negative 4
Sound level, 5560; Safety margin: negative 4 - negative 3

Sound condition: Hill
Sound level, 3840; Safety margin: 6 4 - 2
Sound level, 4045; Safety margin: 2 - 3 - 3 0 - 1 - negative 1
Sound level, 4550; Safety margin: negative 1 - neg 2 - neg 2 - neg 1 neg 2 - neg 2
Sound level, 5055; Safety margin: negative 2 negative 3 - negative 2
Sound level, 5560; Safety margin: --

Sound condition: Baffle
Sound level, 3840; Safety margin: 5 7 - 8
Sound level, 4045; Safety margin: 7 5 - 6 - 2 - 3 - 2
Sound level, 4550; Safety margin: 2 0 - 0 - 0 - 5 - negative 1
Sound level, 5055; Safety margin: negative 1 neg 2 - neg 3 - 1 - neg 4 - neg 3
Sound level, 5560; Safety margin: --

Sound condition: Minor bend
Sound level, 3840; Safety margin: 3 - 5 3
Sound level, 4045; Safety margin: 3 - 8 4 - 5 - 0 - 3
Sound level, 4550; Safety margin: 3 - 2 - 2 - 0 - 1 - negative 2
Sound level, 5055; Safety margin: negative 2 - 1 - 3 - negative 4
Sound level, 5560; Safety margin: negative 4 - 8

Sound condition: Trees
Sound level, 3840; Safety margin: 7 5 - 2
Sound level, 4045; Safety margin: 2 - 3 - 6 - 4 - 2 - 4
Sound level, 4550; Safety margin: 4 - 3 - 3 - 2 - 0 - 1
Sound level, 5055; Safety margin: 1 negative 3 - negative 4
Sound level, 5560; Safety margin: --

Return to article
Return to Home page