Traffic and Highway Engineering
Traffic and Highway Engineering
5th Edition
ISBN: 9781305156241
Author: Garber, Nicholas J.
Publisher: Cengage Learning
bartleby

Concept explainers

Question
100%
Book Icon
Chapter 13, Problem 14P
To determine

The preference of one alternative out of the three based on economic criteria by using the present worth, equivalent annual cost, benefit-cost ratio and rate of return methods.

Expert Solution & Answer
Check Mark

Answer to Problem 14P

Alternative 3- Intersection widening

Explanation of Solution

Given:

Analysis period = 20 years

Annual interest rate = 15 percent

Traffic and Highway Engineering, Chapter 13, Problem 14P

Calculation:

Determine the present worth of alternative 1 (Traffic signals):

  PW1=340,000(10,000+450,000)(P/A1520)+25,000(P/F1520)(P/A1520)= ( 1+i )n1i ( 1+i )n= ( 1+0.15 ) 2010.15 ( 1+0.15 ) 20=6.26(P/F1520)=1 ( 1+i )n=1 ( 1+0.15 ) 20=0.0611PW1=340,000(10,000+450,000)(6.26)+25,000(0.0611)=$3218072.50

Determine the present worth of alternative 2 (Intersection widening):

  PW2=850,000(5,000+300,000)(P/A1520)+12,000(P/F1520)(P/A1520)= ( 1+i )n1i ( 1+i )n= ( 1+0.15 ) 2010.15 ( 1+0.15 ) 20=6.26(P/F1520)=1 ( 1+i )n=1 ( 1+0.15 ) 20=0.0611PW2=850,000(5,000+300,000)(6.26)+12,000(0.0611)=$2758566.80

Determine the present worth of alternative 3 (Grade separation):

  PW3=2,120,000(5,000+225,000)(P/A1520)(P/A1520)= ( 1+i )n1i ( 1+i )n= ( 1+0.15 ) 2010.15 ( 1+0.15 ) 20=6.26PW3=2,120,000(5,000+225,000)(6.26)=$3559800

The project with the highest present worth is alternative 2.

Determine the equivalent annual cost of alternative 1 (Traffic signals):

  EUAW=NPW[i ( 1+i ) n ( 1+i ) n1]EUAW1=3218072.50[0.15 ( 1+0.15 ) 20 ( 1+0.15 ) 201]EUAW1=$514891.60

Determine the equivalent annual cost of alternative 2 (Intersection widening):

  EUAW=NPW[i ( 1+i ) n ( 1+i ) n1]EUAW2=2758566.80[0.15 ( 1+0.15 ) 20 ( 1+0.15 ) 201]EUAW2=$441370.688

Determine the equivalent annual cost of alternative 3 (Grade separation):

  EUAW=NPW[i ( 1+i ) n ( 1+i ) n1]EUAW3=3559800[0.15 ( 1+0.15 ) 20 ( 1+0.15 ) 201]EUAW3=$569568

The project with the highest equivalent annual costis alternative 2.

Determine the benefit-cost ratioof alternative 1 (Traffic signals):

  BCR1=( 10,000+450,000)( P/A1520)+25,000( P/F1520)340,000(P/A1520)= ( 1+i )n1i ( 1+i )n= ( 1+0.15 ) 2010.15 ( 1+0.15 ) 20=6.26(P/F1520)=1 ( 1+i )n=1 ( 1+0.15 ) 20=0.0611BCR1=2878072.5340,000=8.465

Determine the benefit-cost ratio of alternative 2 (Intersection widening):

  BCR2=( 5,000+300,000)( P/A1520)+12,000( P/F1520)850,000(P/A1520)= ( 1+i )n1i ( 1+i )n= ( 1+0.15 ) 2010.15 ( 1+0.15 ) 20=6.26(P/F1520)=1 ( 1+i )n=1 ( 1+0.15 ) 20=0.0611BCR2=1908566.8850,000=2.245>1

Since BCR >1, we would select Alternative 2.

Determine the benefit-cost ratio of alternative 3 (Grade separation):

  BCR3=( 5,000+225,000)( P/A1520)2,120,000(P/A1520)= ( 1+i )n1i ( 1+i )n= ( 1+0.15 ) 2010.15 ( 1+0.15 ) 20=6.26BCR3=14398002,120,000=0.68<1

Since BCR is less than 1, we would not select Alternative 3

Determine the benefit-cost ratio of alternative 2 with respect to 1:

  BCR21=1,908,566.82,878,072.5850,000340,000=1.9

We reachthe same conclusion as previously, which is to select Alternative 2

Determine the rate of return (ROR)of alternative 1versus 2:

  NPW=0=(850,000340,000)(5,000+150,000)(P/Ai20)+(25,00012,000)(P/Fi20)

It is very difficult to solve this explicitly for i. By trial and error, we can easily find the i that makes the right side of the equation equal to the left side.

  510,000=155,000(P/Ai20)+13,000(P/Fi20)

Try i=30%,

  155,000(P/A3020)+13,000(P/F3020)=513911.62

For i=31%

  155,000(P/A3120)+13,000(P/F3120)=497684.2512

Then, we can try i=30.5% and by interpolation 30.237 % is the rate of return to make the left side to equal to the right side.

Since ROR is greater than 15 percent, we select Alternative 2

Determine the rate of return (ROR) of alternative 3 versus 1:

  NPW=0=(2,120,000340,000)(5,000+225,000)(P/Ai20)+(25,0000)(P/Fi20)

By trial and error, we can easily find the i that makes the right side of the equation equal to the left side.

  1,780,000=230,000(P/Ai20)+25,000(P/Fi20)

Try i=11%,

  230,000(P/A1120)+25,000(P/F1120)=1828464.62

For i=12%

  230,000(P/A1220)+25,000(P/F1220)=1715277.50

By interpolation 11.428 % is the rate of return to make the left side to equal to the right side.

Since the ROR is lower than 15 percent, we discard Alternative 3.

Conclusion:

The second alternative i.e. Intersection widening is selected by using the three economic methods.

Want to see more full solutions like this?

Subscribe now to access step-by-step solutions to millions of textbook problems written by subject matter experts!
Students have asked these similar questions
Tables A1E-A12E are the English-Units versions of the Tables A1-A12. Using these tables, determine the specific volume of water at 500 PSI and 50 °F. Show the steps and draw a diagram (like how we did in class) to determine the phase.
What is the formula of B coefficient  beta T and beta C if you will not use any software ?
A flash drum operating at 300 kPa is separating 1000.0 kmol/h of a mixture that is 40.0 mol% isobutane, 25.0% n-pentane, and 35.0% n-hexane. We wish a 90.0% recovery of n-hexane in the liquid. Find Tdrum, xi, yi, and V/F.
Knowledge Booster
Background pattern image
Civil Engineering
Learn more about
Need a deep-dive on the concept behind this application? Look no further. Learn more about this topic, civil-engineering and related others by exploring similar questions and additional content below.
Similar questions
SEE MORE QUESTIONS
Recommended textbooks for you
Text book image
Traffic and Highway Engineering
Civil Engineering
ISBN:9781305156241
Author:Garber, Nicholas J.
Publisher:Cengage Learning
Text book image
Solid Waste Engineering
Civil Engineering
ISBN:9781305635203
Author:Worrell, William A.
Publisher:Cengage Learning,