Errata Sheet Prepared by Dr. Saito for CEEn 562 Text
Traffic Engineering, 4th Edition
By Roger P. Roess, Elena S. Prassas, and William R. McShane
Prentice Hall
Page
Chapte
r5
p.101,
left
column
Chapte
r7
p.124
p.125
p.132,
left col.
p.132,
right
col.
p.133
left col.
p.133
left col.
p.133
left col.
p.333
p.138
p.140,
left col.
p.143,
left col.
Corrections
The unit of SMS is ft/s instead of mi/h. 58.7 mi/h  58.7 ft/s.
Table 7.2. Height groups are incorrectly labeled. Because data has one decimal value,
this has to be reflected. See the first group. The range is 60-62 and the next group is
63-65. Then where does 62.4 belong to? It has to be 60-62.999, and the next one is
63-65,999. So, the number of observations should be from the top to the bottom like:
6, 17, 42, 27, 8.
Equation 7-5. The f and m in the square root for standard deviation formula must have
a subscript i. So, f fi, mmi
2nd paragraph. “… and the standard deviation as σ =Npq=8 x 0.25 x 0.75 = 1.5.”
should be “   Npq  8  0.25  0.75  1.22 ”
3rd paragraph, 3rd line from the end of the paragraph. “…the result X = 1 will occur
10.0%...” should be “…the result X = 0 will occur 10.0%...” OR “…the result X=1
will occur 26.7%...”
12.5 (50 x 0.25) This is confusing.  12.5 (= 50 x 0.25)
9.375 (50 x 0.25 x 0.75) This is confusing.  9.375 (= 50 x 0.25 x 0.75)
Section 7.6.2. The last sentence “Figure 7.4 illustrates the resulting distribution.” This
sentence should be at the end of the second paragraph.
Figure 7.4. The caption should read like “Binomial Distribution for N = 50 and p =
0.25.
Equation 7-16. x1 and x2 needs a bar above them because they are average values. 𝑥̅ 1
and 𝑥̅ 2
At the bottom.
If [Prob F≥F] ≤0.05, then… should be If Prob[Fcomputed ≥ Fcritical] ≤ 0.05
If [Prob F≥F] > 0.05, then… should be If Prob[Fcomputed ≥ Fcritical] > 0.05
The formula for computing t is missing the square root (1/n1+1/n2) term. See below.
p.143,
left col.
This is not a typo, but a bit confusing. To compute Sd using a formula that is
confusing. You can use the basic standard deviation formula for the differences
between procedure 1 and procedure 2 values. See below.
p.144
Table 7.10. X2 column near the bottom. See below.
p.147
Problem 7-7. … sample size n so that…  … sample size N so that …
Chapte
r8
p.151,
Vy = Vx(x/y) should be Vy = Vx(y/x). Several lines below, there is a sample
equation calculation. This sample calculation is correct.
8-1
V5 = 100(5/4) = 125 vehs.
p.152,
A couple of numbers in Table 8.1 are incorrect. See below.
Table
8.1
Chapte
r9
p.169,
right
col.
p.175,
left col.,
2nd para.
p.176,
left col.,
2nd para.
p.185,
right
col.
p.186,
left col.
Chapte
r 10
p.205,
left col.
2nd paragraph from the bottom. “Figure 5 shows…of annual average daily travel
[ADT] in …” should read like “Figure 5 shows…of annual average daily traffic
[AADT] in …”
“For signalized approaches, the size of the queue would be recorded at the beginning
of each red phase. This identifies the “residual queue” of vehicles that arrived during
the previous signal cycle but were not serviced.” This is a bit confusing statement
because in reality the residual of queue at the end of counting period is needed, not at
the beginning of each red phase. So, when we do this kind of volume study, we need
the number of queued vehicles at the end of counting period i. This means you count
the number of vehicles in the queue at the beginning of the first red phase of the next
count period i+1.
“For a 90-second cycle, however, neither 4 or 5 minutes are equal multiples of 90
seconds (1.5 minutes). For a 90-second cycle, a counting process of 12 of 15 minutes
would be appropriate, as would 4.5 of 6 minutes.” I think you can count for 13.5
minutes (9 cycles) of 15 minutes (10 cycles). Please note this type of counting is done
for manual counting. When we use Jamar counter, we simple keep counting and ask
the software to extract the sum total for each counting period.
Table 9.8 and Figure 9.14 are not related; they are talking about different things.
First sentence. “The daily variation factors are plotted against the midpoint of the
week…” should be “The monthly variation factors are plotted…”
See the type shown below.
p.214,
left col.
p.214,
left col.
p.214
right
col.
p.216,
right
col.
p.217,
right
col.
p.220
right
col.
p.221
right
col.
p.223,
left col.
p.223,
right
col.
p.224,
right
col.
Chapte
2nd paragraph, 4th line. “…for travel times would be…” should read “…for running
times would be…”
The denominator of S2 should be 166.6 instead of 1666.6.
Right below the un-numbered table. “The observation of Table 10.4…” should read
“The observation of Figure 10.3 …”
First equation. It’s just confusing.
𝑁≥
8,486
∆2
should be 𝑁 ≥
1.6452 ×282
∆ 2
2
( )
Section title “10.3.3 Travel-Time Displays” should read “10.3.4 Travel-Time
Displays.”
The description for Observer 1, 2nd bullet. This statement contradicts what’s written in
p.16-90 of HCM 2000. In HCM 2000, it goes like “… should not be an integral
divisor of the cycle length.” But, if you look at the form in Figure 10.9, which came
from HCM 2000, the authors’ statement is more logical.
Unit of VSLC. Right column, near bottom. The unit of VSLC is “veh/ln/cycle” not
“vehs.”
Problem 10.1
(b) Determine…in the pact from the curves, …” should be “Determine…in the pace
from the curves,…”
(e). “…a second is to be conducted…” should read “…a second speed data collection
is to be conducted…”
Problem 10.3. At the bottom right just below the table, there is a number “223.” Erase
this number. It is not used for any part of the computations.
Problem 10-5 (b). Ignore the first sentence of this problem. It does not make sense.
The authors might have wanted to say “Section 10-3” instead of “Problem 10-3.”
Also, tolerance should read ±3 mi/hr instead of ±3 to make it clear the unit used for
the calculation.
r 11
p.247
Chapte
r 13
Chapte
r 14
p.288
p.293
p.294
p.299
p.304
p.307
Table 11:4. Key 13. “Provide lurn lane”. This must be “Provide turn lane.”
This is not a typo, but
Can you explain equation 11-4? Try if you can reason why this is correct. Hint: For a
random distribution (Poisson distribution), mean and variance are equal. So, if fA is
the number of accidents in the “after” period (expected value), then its variance is fA
also. Now, use equation 7-8. To get z = (x1 – mean)/standard deviation. x1 can be in
this case the difference (fB - fA), and since we have two populations, we need to pool
the variances, meaning (fB + fA). Its standard deviation is square root of (fB + fA).
None.
Table 14.1. It refers to Figure 14.1. It should refer to Figure 14.2.
Table 14.6. Right shoulder lateral clearance 1ft for 2 lanes in one direction is 3.0
instead of 2.0.
Left column. 2nd paragraph. The word “affect” was used incorrectly twice. They
should be “effect.”
Table 14.12. 10% column, >4-5% upgrade, >1.00 mile row, ET = 3.5 instead of 2.5.
Figure 14.7. “Sample Problem 1” should be “Sample Problem 14.4.
Table 14.15. There are typos and miscalculations.
Because of this change in SV, Step 6 needs to be fixed. The correct equation to find n
is:
5910 = 3600(1.06n)
p.308
Chapte
r 15
p.322
Hence, n = 8.50 instead of 7.63.
Example 14-7. Step 1 free flow speed calculation. FFS = 73.6 mph instead of 74.8
mph.
Figure 15.4. “(c) … Single-Lane Raps” should read like “…Single-Lane Ramps.”
p.324
p.327
p.336
p.337
p.339,
right
column
In the subsection “Numerical Characteristics of Two-Sided Weaving Configurations.”
“In both Figures (b) and (c)” should read like “In both Figures (c) and (d).”
In Figure 15.8. Nw is supposed to be Nwv.
In Figure 15.12. In the first box for off-ramp. “… in Lanes 1 and 3 immediately
upstream…” should read like “… in Lanes 1 and 2 immediately upstream…”
In Table 15.3. For 6 lane freeways. Second equation (Eq. 15-26) should start like
“PFM =” instead of “PF =”
Equation 15-38 and 15-39. Typos shown below. Capital letters are for volumes and
small letters are for flow rates. Here, we use flow rates. So, we need small letters.
p.341
Right column. 4th bullet.
“VR12 = V12 + VR” should be “vR12 = v12 + vR”
In Table 15.6 for All Lanes row.
p.342
In Table 15.7. for All Lanes row.
p.343,le
ft col.
It is not a typo but a bit confusing. It is better to label them as shown below because
the corrected ones are used in subsequent equations.
p.340
p.343,
right
col.
p.344,
left col.
p.344,
right
col.
Step 4. … is estimated using Equation 14-4. This should be Equation15-4.
p.346347
The following errors are found.
p.346, right col.
6th equation. CIW should be cIW.
The following errors are found in the right column of page 344.
p.347,
p.348,
left col.
p.348,
left col.
p.349,
left col.
p.351,
left col.
p.362,
left col.
p.364,
right
col.
In Step 2, in the last sentence right above the PFM calculation. “Then, Equation 15-32
is used…” should read “Then, Equation 15-24 is used…”
In Step 3, right below the vFO calculation. “From Table 15.3…” should be “From
Table 15.5…”
The result of the computation is 58.1 mph and NOT 57.2 as you see in the page!
In Step 3, 2nd line of the first paragraph. “…performed in Table 15.8…” should be
“…performed in Table 15.5…”
Please ignore the following 5 rows. These typos were found in the 3rd edition and I am
not sure about them in the 4th edition. I have not checked Appendix of Chapter 15 yet.
We don’t cover it this semester, fall 2013.
D = … = 26.3 pc/min/ln should be D = … = 26.3 pc/mi/ln
This computation is completely wrong. It came from the assumption that Appendix I
Table E is meant for 75 mph and 70 mph FFS. However, HCM2000 shows that Table
E is meant for 75 mph FFS only. The next table is 65 mph FFS. So, to get necessary
values for VR=0.4 and VR=0.5, we need to interpolate corresponding table values.
See the computation below.
p.365,
left col.
Appendi
xI
p.385,
right
col.
Chapte
r 18
p.415,
right
column
Chapte
r 19
p.440
Chapte
r 20
p.481
“Table 13.8 is used to obtain…” should read “Table 12.13 is used to obtain…”
All tables that says “….-75 mi/h Free-Flow Speed and 70 mi/h FFS” are incorrect.
They should read “… - 75 mi/h Free-Flow Speed.”
Right below the PFD values. “Also, the length of the acceleration lane…” should read
“Also, the length of the deceleration lane…”
See the typo shown below. It is 34 in the numerator. It is supposed to be 36.
Table 19.3. Third field name: No. of Lanes on Arterial1. This should be Arterial 1.
Eq. 20-18. A fatal typo! They forgot to square the first bracket! The correct one is:
1
1
𝑣𝑠
𝑔
𝑈𝐷𝑎 = 𝑅𝑉 = 𝐶 2 [1 − ⁄𝐶 ]2 [
]
2
2
𝑠−𝑣
p.484
Example 20-1. Small letter c was supposed to be used.
p.485
Example 20-3.
p.487,
left col.
p.488
Problem 20-8, (c). ET should be ELT.
Chapte
r 21
p.503,
right
col.
p.504,
left col.
p.508,
Problem 20-12. v=800 vph is missing from the problem statement. Also, Akcelik’s
model cannot solve Problem 20-12-c. The model is not set up for that.
Equation 21-3a. Small letter w. There is no definition given to this w. This is “width
of street being crossed.”
Eq. 21-4. “where: S85 = 85th percentile speed, mi/h” should read “where: S15 = 15th
percentile speed, mi/h”
Second equation.
left col.
p.508,
right
col.
p.509,
left col.
gA1+A2 = 58*(252/1100) = 13.2 s
should look like:
gA1+A2 = 58*(250/1100) = 13.2 s
Nped definition. “…crossing per phase in a single…” should be “… crossing per cycle
in a single…”
Eq. 21.16 should be like:
p.510,
left col.
Top.
p.511,
right
col.
p.512
GpA = 20.0 ≥ GA + … should be GpA = 20.0 < GA + …
GpA = 30.0 ≥ GB + TB = … should be GpB = 30.0 ≥ GA + YB =…
p.519,
left col.
The top equation after = sign. Now it shows “= 5 sec”. It should be “5.9 sec.”
Chapte
r 22
p.530,
right
col.
Inside Example 21-1.
 EB: VLT = 10 < 20 should be like,
 EB: VLT = 10 < 200
Inside Table 21.4 as shown below.
Bullet d.
“d. Time into the green that gap reduction ends, t2 (s)” should be
“d. Time to reduce the gap from maximum gap to minimum gap, t2 (s)” to agree with
p.537,
left col.
the notation in Figure 22.4 and this is the typical definition of t2.
Last line right above Example 22-1.
“to for major-street through phases during light” should be “for major-street through
phases during light.”
p.539,
right
col.
p.541,
left col.
Step 2 should look like:
p.541,
right
col.
p.541,
right
col.
The first sentence, toward the end. “Int (50/20) = 3.0 seconds.” should be “Int (50/25)
= 2 vehicles.”
p. 542,
left col.
Right below equations. 2nd line in the paragraph should look like:
Chapte
r 24
p.573,
right
col.
Top right should look like:
Bullet 2. “…now partially modelled” should be “…now partially modeled”
p.576,
right
col.
Equation 24-4. The subscript of X should be small letter c, not capital letter C.
p.577,
left col.
Equations 24-5 and 24-6. In both cases, the subscript of X should be small letter c, not
capital letter C.
p.583,
left col.
Table 24.4. It says Relationship between platoon ratio and arrival type. But, there’s
no platoon ratio shown in the table. This is the original one.
p.590,
left col.
p.592,
right
col.
p.595,
left col.
p.596,
left col.
p.596,
right
col.
p.596,
3rd line from the bottom. “All other variables as are as previously defined.” should
read “All other variables are as previously defined.”
3rd line, 2nd paragraph. “as shown in Figure 24.8” should be “as shown in Figure 24.7”
1st bullet. Last sentence. “using Equation 24-8 for the known arrival type” should be
“using Equation 24-26 for the known arrival type.”
Equation 24-35. The + sign after 900T must be *, that is, this is a multiplication, not
addition.
The first sentence would be clearer if written this way. “filtering/metering adjustment
factor, I, is only used in …”
Right below a subheading “Initial Queue Delay.” “Equation 24-35 is used” should be
right
col.
p.599,
left col.
“Equation 24-36 is used.”
p.600,
left col.
In Table 24.9. This one I made a mistake. N=3 is correct, but the computed value is
wrong: it is 0.933.
p.601,
left col.
p.601,
left col.
In 24.4.1 at the end of the Input subsection.
N=3 is correct. The result = 0.933 instead of 0.950, though.
In Table 24.11.
In Table 24.12.
p.602,
left col.
p.602,
left col.
Right above Step 1 in Equation (25-30). 60/25.4 must be 60/26.4.
p.602,
right
col.
See corrections for EBTH in Table 24.13
Step 3 and 6.
p.603,
left col.
In Table 24.14.
p.603,
right
col.
In Table 24.15.
p.610,
left col.
The first equation, starting with C = ….. = 745 s. This should be C = … = 75.5 s as
shown below.
Chapte
r 26
p.635,
right
col.
p.636,
left col.
p.643,
left and
right
col.
p.645,
left col.
Bullet 3: MSG = Main Street Green. This is not defined in anywhere in the textbook.
2nd sentence of the 3rd paragraph of section 26.2.2.
“In this case, the bandwidth impact of underestimation the platoon speed is (60ft/s
instead of 70 ft/s) is not as…” The first “is” should be removed.
Left col. Step 3: “Recognizing that the westbound vehicles…” should be
“Recognizing that the eastbound vehicles…”
Right col. Step 7: “…the start of green facing east” should be “…the start of green
facing west.”
3rd paragraph, last statement. “3600(40)(2)(2.0)(120) = 1,200 veh/h,” should be
“3600(40)(2)/((2.0)(120)) = 120. (Add the division sign between 2 and 2.0.) If you
want to check, simply do the math. The value of the mistyped equation gives
69,120,000 veh/h!!!