Using the figure and the included equations, determine the following: a. The signal phasing plan that will yield the minimum cylce length (assuming 95% capacity utilization (Xc) and three timing stages). (Hint: First determine N-S phasing possibilities and E-W phasing possibilities, and then consider possible combinations). Use the attached equation for Cmin. b. "Optimal" cycle length. Use the attached equation for Copt. c. Effective green times for each phase (for balanced v/c ratios), for minimum cycle. Use the attached equation for gi. d. Displayed yellow and all-red times for each phase. Use the attached equations for Y and AR. e. Required pedestrian green times. Use the attached equations for Gp.
Using the figure and the included equations, determine the following:
a. The signal phasing plan that will yield the minimum cylce length (assuming 95% capacity utilization (Xc) and three timing stages). (Hint: First determine N-S phasing possibilities and E-W phasing possibilities, and then consider possible combinations). Use the attached equation for Cmin.
b. "Optimal" cycle length. Use the attached equation for Copt.
c. Effective green times for each phase (for balanced v/c ratios), for minimum cycle. Use the attached equation for gi.
d. Displayed yellow and all-red times for each phase. Use the attached equations for Y and AR.
e. Required pedestrian green times. Use the attached equations for Gp.
![where
X₂
where
Cmin = minimum necessary cycle length in seconds (typically rounded up to the
nearest 5-second increment in practice),
total lost time for cycle in seconds,
critical v/c ratio for the intersection,
LXX
L =
X =
(v/s)a= flow ratio for critical lane group i, and
n = number of critical lane groups.
Copt=
Σ(;)
where
1.5XL +5
1.0-
i=1
Coptcycle length to minimize delay in seconds, and
other terms are as defined previously.
*-0.6
g; = effective green time for timing stage i,
(v/s) a = flow ratio for critical lane group i,
C = cycle length in seconds, and
X₁ = v/c ratio for lane group i.
where
Y=1, +
where
V
2a + 2gG
Y = yellow time (usually rounded up to the nearest 0.5 seconds),
t₁ = driver perception/reaction time, usually taken as 1.0 second,
V = speed of approaching traffic in ft/s,
a = deceleration rate for the vehicle, usually taken as 10.0 ft/s²,
g = acceleration due to gravity [32.2 ft/s²], and
G= percent grade divided by 100.
AR=W+1
V
AR = all-red time (usually rounded up to the nearest 0.5 seconds),
w = width of the cross street in ft,
/= length of the vehicle, usually taken as 20 ft, and
V = speed of approaching traffic in ft/s.
= 3.2+ ++(0.27N) for Wg ≤10ft
G₁ =32+ = - + (27)
+2.7-
WE
for WE > 10 ft
where
G₂ = minimum pedestrian green time in seconds,
3.2 = pedestrian start-up time in seconds,
L = crosswalk length in ft,
Sp walking speed of pedestrians, usually taken as 3.5 ft/s,
Nped number of pedestrians crossing during an interval, and
WE = effective crosswalk width in ft.](/v2/_next/image?url=https%3A%2F%2Fcontent.bartleby.com%2Fqna-images%2Fquestion%2F40578013-3e17-4421-b4af-d1f1eb4da799%2F93ab3479-8526-46c5-a1b9-121c5611c6cd%2F7tp9pfm_processed.png&w=3840&q=75)


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