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Sub-problem 2d - Page 5 of 7 |
ID# C402D05 |
Sub-problem 2d: How
Can We Improve the Level of Service at the Ramp Junction at the Northbound On-Ramp to
I-87?
Exhibits 4-35 and 4-36 show the
effect of adding a lane to the ramp so that two lanes are maintained on the
ramp for its entire length from Alternate Route 7 to I-87 North.
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Exhibit 4-35. Additional Ramp Lane
Input Data |
| Freeway data |
PM Peak
(Before) |
PM Peak
(After) |
|
Dataset 21 |
Dataset 22 |
| Number of lanes, N |
3 |
3 |
| Free flow speed, SFF |
55 |
55 |
| Volume |
4,800 |
4,800 |
| Ramp data |
PM Peak
(Before) |
PM Peak
(After) |
| Ramp volume |
1,900 |
1,900 |
| Number of lanes on-ramp, N |
1 |
2 |
| Length of acceleration lane, LA |
500 |
500 |
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Exhibit 4-36. Additional Ramp Lane Output Data |
| |
PM Peak
(Before) |
PM Peak
(After) |
| Output data |
Dataset 21 |
Dataset 22 |
| PFM |
0.59 |
0.56 |
| V12, pc/h |
3,154 |
2,960 |
| VFO actual |
7,444 |
7,444 |
| VFO maximum |
6,750 |
6,750 |
| VR12 actual |
5,265 |
5,071 |
| VR12 maximum |
4,600 |
4,600 |
| Density, pc/mi/lane |
42.5 |
34.7 |
| LOS for ramp-freeway junction area of
influence |
F |
F |
| Speed-ramp influence area, mph |
41.6 |
44.5 |
| Speed-outer lanes, mph |
49.0 |
48.0 |
| Speed-all vehicles, mph |
43.5 |
45.6 |
After reviewing the output data
shown in Exhibit 4-36, consider the following questions:
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What is the most significant change in the performance
of the merge area as a result of the addition of the lane to the freeway
mainline? |
| Does the addition of the lane produce acceptable
performance of the merge area? |
Discussion:
 Take a few minutes to consider
these questions. When you are ready, continue to the next page.
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