MaryJ
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- Feb 8, 2010
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I just worked a problem and came up with a Radius of 5729.578 and a HSO value of 23.32.
The problem basically ask for the safe design speed of a highway, given D=(9 degrees, 30 minutes), lanes are 12 feet wide and a continuous tree hedge is located along the inside of the curve, exactly 29.32 ft from center of the highway. PI= 16+00
my solution:
R= 5729.578/9.5= 603.11 (radius of roadway centerline)
Determine the radius of the centerline of the inside lane (603.11 - 6')= 597.113'
Find actual HSO distance: 29.32 - 6' = 23.32'
Now the problem continue by stating that I should plug R and HSO values into CERM Eq 79.44 (CERM 10-th edition) to get a "S" value of 335'
Is there an error in the solution of the problem as I have plug these values into the equation a couple of times and cannot come up with this answer.
formula:
S = ( R/28.65 )( arccos (( R-M )/R )
The problem basically ask for the safe design speed of a highway, given D=(9 degrees, 30 minutes), lanes are 12 feet wide and a continuous tree hedge is located along the inside of the curve, exactly 29.32 ft from center of the highway. PI= 16+00
my solution:
R= 5729.578/9.5= 603.11 (radius of roadway centerline)
Determine the radius of the centerline of the inside lane (603.11 - 6')= 597.113'
Find actual HSO distance: 29.32 - 6' = 23.32'
Now the problem continue by stating that I should plug R and HSO values into CERM Eq 79.44 (CERM 10-th edition) to get a "S" value of 335'
Is there an error in the solution of the problem as I have plug these values into the equation a couple of times and cannot come up with this answer.
formula:
S = ( R/28.65 )( arccos (( R-M )/R )
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