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For designing a 2-phase fixed type signal at an intersection having North-South and East-West road where only straight ahead traffic permitted, the following data are available.
Total time lost per cycle is 12 seconds. The cycle length (seconds) as per Webster’s approach is
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- 67
- 77
- 87
- 91
- 67
Correct Option: B
In N-S direction : Higher flow = 1000, saturation flow = 2500
| ∴ y1 = | = 0.4 | |
| 2500 |
In E-W direction : Higher flow = 900, saturation flow = 3000
| y2 = | = 0.3 | |
| 3000 |
Y = y1 + y2 = 0.7
Lost time per cycle, L = 2n + R = 12 s
| Optimum cycle time = | ||
| 1 - 4 |
| = | = 77 | |
| 1 - 0.7 |
