Concept explainers
The number of additional lanes required in each direction.
Answer to Problem 8P
The number of additional lanes required to maintain the level of service B is four.
Explanation of Solution
Given:
Length of the segment is
Sustained grade is
Design volume is
Percentage of trucks is
Percentage of buses is
Percentage of RV's is
Percent hour factor is
Free flow speed is
Right side lateral obstruction is
Design LOS is
Formula used:
Write the expression to calculate the
Here,
Find the number of lanes in each direction using the following relation.
Here,
Calculate the free flow speed by using the formula.
Here,
Write the expression to calculate the speed.
Here,
Write the expression to calculate the density using the formula.
Here,
Calculation:
Refer table 9.26, "PCE's for trucks and buses on upgrades, multilane highways and basic freeway sections".
The value of passenger car equivalent for trucks
The value of passenger car equivalent for recreational vehicles is
Substitute
Consider the driver population factor as
Consider
Substitute
Consider
Substitute
Consider
Substitute
Refer table 9.29, "Adjustment for lane width".
The value of
Refer table 9.30, "Adjustment for right shoulder lateral clearance".
At the right side lateral clearance, the value of reduction in free flow speed
For two lanes the value is
For three lanes the value is
For four lanes the value is
Refer table 9.31, "Adjustment for number of lanes" for the value of
For two lanes the value is
For three lanes the value is
For four lanes the value is
Refer table 9.32, "Adjustment for interchange density" for the value of
The value is
Consider
Substitute
Substitute
Substitute
Refer table 9.33, "Level of service criteria for multilane highways".
The level of service is D.
Consider
Substitute
Substitute
Substitute
Refer table 9.33, "Level of service criteria for multilane highways".
The level of service is C.
Consider
Substitute
Substitute
Substitute
Refer table 9.33, "Level of service criteria for multilane highways".
The level of service is B.
Conclusion:
Therefore, the number of additional lanes required to maintain the level of service B is four.
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Chapter 9 Solutions
Traffic and Highway Engineering - With Mindtap
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