Sub-problem 2d: How Can We Improve the Level of Service at the Ramp Junction at the Northbound On-Ramp to I-87?
The table below shows 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.
| Freeway data | PM Peak (Before) | PM Peak (After) |
| 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 |
| Output data | PM Peak (Before) | PM Peak (After) |
| 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 the table above, consider the following questions:
-
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.