Case Study 1Problem 5

Styner/Lauder IntersectionMoscow, Idaho

Problem 5: U.S. 95 South of Moscow

How will U.S. 95 operate in the future?

1100 veh/hr in PM peak

700 trips from new development

400 trips from hamlet

Problem 5: U.S. 95 South of Moscow

How should this problem be defined and analyzed?

Problem 5: U.S. 95 South of Moscow

What are the possible options?

What analysis plan should be followed?

Existing analysis of 10-mile segment

Future analysis of 10-mile segment

Analysis of 10-mile segment with bypass

Sub-problem 5a: Existing Analysis of 10-Mile Segment of U.S. 95

What data are required for analysis?

What other factors should be considered?

What measure should be used to determine the performance of the facility?

Sub-problem 5a: Existing Analysis of 10-Mile Segment of U.S. 95

What data are required for analysis? ADT = 600 veh/hr Shoulder widths = 6 ft Lane widths = 12 ft Directional split = 54/46 PHF = 0.88 %trucks/buses = 10% Free flow speed = 60

mph %no pass zones = 30 2 access points/mile

Sub-problem 5a: Existing Analysis of 10-Mile Segment of U.S. 95

What other factors should be considered?

Class I facility

What measure should be used to determine the performance of the facility?

Travel speed Percent time following

Results 52.4 mph 55.7% time following LOS = C

Sub-problem 5b: Future Analysis of 10-Mile Segment of U.S. 95 With Direct Recognition of the Hamlet

Consider these issues

What can be done to assess the future performance characteristics of the one-mile section of U.S. 95 that passes through the hamlet?

How can the estimated performance characteristics of the section of U.S. 95 that is within the hamlet be incorporated into an overall assessment of the 10-mile segment?

Sub-problem 5b: Future Analysis of 10-Mile Segment of U.S. 95 With Direct Recognition of the Hamlet

Consider these issues

What can be done to assess the future performance characteristics of the one-mile section of U.S. 95 that passes through the hamlet?

How can the estimated performance characteristics of the section of U.S. 95 that is within the hamlet be incorporated into an overall assessment of the 10-mile segment?

Sub-problem 5b: Future Analysis of 10-Mile Segment of U.S. 95 With Direct Recognition of the Hamlet

Here are some issues to consider as you proceed with the analysis of the future conditions. What volumes should be used in the future conditions

analysis? What additional assumptions are necessary for the

analysis? What common measure should be used to determine

the performance of the facility throughout the various sections?

Sub-problem 5b: Future Analysis of 10-Mile Segment of U.S. 95 With Direct Recognition of the Hamlet

Input data: Volumes? Other

factors?

Sub-problem 5b: Future Analysis of 10-Mile Segment of U.S. 95 With Direct Recognition of the Hamlet

The HCM procedure assumes rank 1 movements do not yield to lower-ranked movements.

Why, then, is delay reported for the NB and SB through- and right-turn movements?

Sub-problem 5b: Future Analysis of 10-Mile Segment of U.S. 95 With Direct Recognition of the Hamlet

Overall assessment: one approach

Sub-problem 5c: 10-Mile Analysis with a By-Pass

Exhibit 1-47. Comparative Results Using the Unsignalized Analysis Northern Section Hamlet Southern Section Overall

Condition Speed mph

Time min

PTSF %

Speed mph

Time min

PTSF %

Speed mph

Time min

PTSF %

Speed mph

Time min

PTSF %

Existing Conditions - - - - - - - - - 52.4 11.5 55.7

Raw Results 48.4 5.6 72.6 24.3 2.5 71.6 52.4 5.2 55.7 45.5 13.2 64.9 Adjusted Results 48.4 5.6 72.6 24.3 2.5 100.0 52.4 5.2 55.7 45.5 13.2 67.7 Using Unsignalized 48.4 5.6 72.6 24.3 1.8 100.0 52.4 5.2 55.7 47.9 12.5 67.7

With Bypass 48.4 4.3 72.6 51.3 4.8 58.5 52.4 4.0 55.9 50.7 13.1 63.7

Sub-problem 5: Discussion

What have we learned in this problem?

The existing HCM procedure for two-lane highways has some limitations

An alternative methodology might provide important insights

The results may be useful in determining the proper course of action