The monthly average daily traffic for the month of July is 8900 and the seasonal factor for the month of July is 0.857. What is the monthly average daily traffic for the month of December if the seasonal factor for the month of December is 0.966?
- A7370
- B10030Correct
- C10385
- D9210
Solution
Concept
The Seasonal Factor accounts for variations in traffic volume across different months of the year relative to the Annual Average Daily Traffic (AADT).
Formula
SF = MADT / AADT AADT = MADTJuly / SFJuly MADTDec = AADT × SFDec
Step-by-step solution
1. Calculate Annual Average Daily Traffic (AADT): AADT = MADTJuly / SFJuly = 8900 / 0.857 = 10385 vehicles/day 2. Calculate Monthly Average Daily Traffic for December (MADTDec): MADTDec = AADT × SFDec = 10385 × 0.966 = 10031.9 ≈ 10030 vehicles/day.
Explanation
Seasonal factor (SF) for a month is defined as the ratio of Monthly Average Daily Traffic (MADT) to Annual Average Daily Traffic (AADT), i.e., SF = MADT / AADT. Using July's data, AADT is calculated as 8900 / 0.857 = 10385 vehicles/day. Using this AADT, the MADT for December is 10385 × 0.966 = 10031.9 ≈ 10030 vehicles/day.
Why the other options are wrong
A: Calculated by incorrectly multiplying MADT of July by SF of July and then dividing by SF of December. C: Represents the Annual Average Daily Traffic (AADT) instead of December's MADT. D: Result of incorrect arithmetic manipulation of seasonal factors.
Shortcut
MADTDec = MADTJuly × (SF
Correct answer: B) 10030