| |
| | |
|
The table below shows the volumetric data observed at an intersection.
Calculate the peak hour volume, peak hour factor (PHF), and the actual (design)
flow rate for this approach.
Table 1:
Volumetric data
| Time interval |
Cars |
| 4:00 - 4:15 |
30 |
| 4:15 - 4:30 |
26 |
| 4:30 - 4:45 |
35 |
| 4:45 - 5:00 |
40 |
| 5:00 - 5:15 |
49 |
| 5:15 - 5:30 |
55 |
| 5:30 - 5:45 |
65 |
| 5:45 - 6:00 |
50 |
| 6:00 - 6:15 |
39 |
| 6:15 - 6:30 |
30 |
|
We can locate the hour with the highest volume and the 15 minute interval with
the highest volume.
The peak hour is shown in blue below with the peak 15 minute period shown in
bold font.
Table 2:
Solution of the problem
| Time interval |
Cars |
| 4:00 - 4:15 |
30 |
| 4:15 - 4:30 |
26 |
| 4:30 - 4:45 |
35 |
| 4:45 - 5:00 |
40 |
| 5:00 - 5:15 |
49 |
| 5:15 - 5:30 |
55 |
| 5:30 - 5:45 |
65 |
| 5:45 - 6:00 |
50 |
| 6:00 - 6:15 |
39 |
| 6:15 - 6:30 |
30 |
|
The peak hour volume is just the sum of the volumes of the four 15 minute
intervals within the peak hour (219).
The peak 15 minute volume is 65 in this case.
The peak hour factor (PHF) is found by dividing the peak hour volume by four
times the peak 15 minute volume.
The actual (design) flow rate can be calculated by dividing the peak hour
volume by the PHF, 219/0.84 = 260 vehicles/hr, or by multiplying the peak 15
minute volume by four,
 vehicles per hour.
|
|
| | |
|
|
|
