(32SII) Stopping Sight Distance

[Eddie W. Shore]

Input:

Y: speed of vehicle or design speed (mi/hr)
X: grade of the road (i.e. for 1% grade enter as 1)

Output:

X: Stopping Sight Distance (in feet)

Formula used:
SSD = 55/15 * V + 1.075*V^2/(11+.32*G)

Assumptions:
* Total reaction time is 2.5 seconds. The deceleration rate of the vehicle is 11 ft/s^2. Both values are recommended by the AASHTO (American Association of State Highway and Transportation Officials).

Program:

S01 LBL S
S02 0.32
S03 *
S04 11.2
S05 +
S06 1/x
S07 1.075
S08 *
S09 x<>y
S10 ENTER
S11 R-down
S12 x^2
S13 *
S14 R-up
S15 55
S16 *
S17 15
S18 ÷
S19 +
S20 RTN

Size: 54.0
Checksum: 2343

Examples:

Input:
Y: 65 (V)
X: 2 (G)
Result (Fix 4): 621.9376 ft

Input:
Y: 35 (V)
X: -4 (G)
Result: 261.0828


Reference:

Source: Goswami, Indramil Ph.D. P.E. "All In One Civil Engineering PE Breadth and Depth Exam Guide" 2nd Edition. McGraw Hill: 2012