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GATE CE 2020 Official Paper: Shift 2

CT 1: Ratio and Proportion

2846

10 Questions
16 Marks
30 Mins

**Concept:**

**Annual Average Daily Traffic (AADT)**: It is the average **24-hour** traffic volume at a given location over a period of 365 days.

It helps in deciding the importance of route and road development. It includes **seasonal variation** also.

It is not feasible to take traffic reading continuously and hence reading is taken periodically and expansion factors are used to convert traffic data into AADT.

**1) Hourly Expansion Factor** \(=\frac{Total~24-hr~volume}{Volume~for~particular~hour}\)

**2) Daily Expansion Factor **\(=\frac{Average~total~week~volume}{Average~voluem~of~a~day}\)

**3) Monthly expansion factor **\(=\frac{Average~annual~daily~traffic}{ADT~of~a~month}\)

**Calculation:**

Given,

24-hr traffic count = 1000 veh

Daily adjustment factor = 1.121

∴ Average week volume = Daily adjustment factor × 24-hr traffic count

= 1000 × 1.121 = 1121 veh

Monthly adjustment factor = 0.913

∴ AADT = Monthly adjustment factor × Average week volume

= 0.913 × 1121 = 1023.47 =