The correct relationship between Average Daily Traffic (ADT), Traffic Volume Count, Daily Factor (DF), Seasonal Factor (SF) is
- A(normal time − crash time)/(crash cost − normal time)
- BADT = (DF × SF)/Traffic Volume Count
- CTraffic Volume Count = ADT × DF × SF
- DADT = Traffic Volume Count × DF × SFCorrect
Solution
Concept
Relationship between ADT and traffic factors
Formula
ADT = Traffic Volume Count × DF × SF
Step-by-step solution
1. Average Daily Traffic (ADT) adjusts short-term volume counts for temporal variations across days and seasons. 2. The relation applies daily and seasonal expansion factors directly to the sampled count. 3. Therefore, ADT = Traffic Volume Count × DF × SF. Answer: D
Explanation
Average Daily Traffic represents the estimated annual daily volume derived by adjusting short-term volume counts. To convert a short-duration traffic count into an accurate daily average, the count must be multiplied by both daily and seasonal adjustment factors. Consequently, the correct mathematical relationship is ADT equals Traffic Volume Count multiplied by DF and SF, making option D correct.
Why the other options are wrong
A) This formula expresses cost-time slope in project management rather than traffic volume factors. B) Daily and seasonal factors must multiply the traffic volume count rather than divide it. C) ADT is calculated by multiplying traffic volume count by DF and SF, not by setting traffic volume count as the product.
Shortcut
Average Daily Traffic (ADT) = Traffic Volume Count × Daily Factor × Seasonal Factor.
Common mistake
Selecting option C by assuming ADT is multiplied by factors to obtain Traffic Volume Count instead of the reverse.
Correct answer: D) ADT = Traffic Volume Count × DF × SF