Overview

Introduction

Getting Started

Problem 1:
In this case study, two basic freeway sections exist on Route 7 between I-87 and I-787, both eastbound and westbound. The basic freeway sections are approximately three miles in length and each direction has characteristics that are unique. In this problem we will look at traffic flow characteristics and analysis of a basic freeway section.

Sub-problem 1a - Traffic flow patterns
Sub-problem 1b - Selection of Appropriate Data and Basic Freeway Analysis
Sub-problem 1c - Basic Freeway Analysis

Problem 2:
This problem focuses on the interchange complex on the western end of Alternate Route 7. The interchange between I-87 and Alternate Route 7 is a classic trumpet with the semi-direct ramp linking Alternate Route 7 west to I-87 south. The Alternate Route 7/U.S. 9 interchange is a partial-cloverleaf. In this problem we will consider two specific procedures from the HCM, one to analyze weaving sections and the other to analyze ramp junctions.

Sub-problem 2a Analysis of the I-87/Alternate Route 7 interchange
Sub-problem 2b Weaving section LOS in the I-87/Alternate Route 7
Sub-problem 2c Ramp and ramp junction LOS for the on-ramp from Alternate Route 7 to I-87 northbound
Sub-problem 2d Mitigation techniques for the on-ramp from Alternate Route 7 to I-87 northbound

Problem 3:
Problem 3 focuses on weaving and ramp analysis. As part of this problem, nonstandard weaving and ramps are analyzed, as is a collector/distributor roadway that isn't easily categorized into an HCM chapter.

Sub-problem 3a Analysis of a weaving section
Sub-problem 3b Freeway ramp analysis
Sub-problem 3c Non-standard ramp and weave analysis in the southwestern quadrant
Sub-problem 3d Analysis of a collector/distributor road

Problem 4:
In the previous three problems of this case study, we examined the operation of individual segments of Alternate Route 7, including basic freeway segments, weaving sections, and ramp junctions. In this problem, we will step back and consider the segments as drivers actually see them: part of a complete freeway facility.

Sub-problem 4c - What is the operational performance of Alternate Route 7 during the peak period?

Problem 5:
This problem demonstrates how a network simulation model can be used to augment studies conducted with HCM methodologies. Simulation models offer the advantage of being able to examine networks of highway facilities in a highly unified, holistic fashion. Inter-dependencies and cascading effects can be taken into account as can traffic variations of time, over saturation, queue length fluctuations, lane blockages, and other transient phenomena