Overview

Printable Overview, Introduction, and Getting Started

This case study investigates a situation at the University of Florida regarding the impacts of a new parking structure on Museum Road in Gainesville, Florida. The increased traffic to and from the new structure would access this facility via a two-way stop-controlled intersection, but alternatives are being analyzed to determine the best solution for this and adjacent intersections along Museum Road. Pedestrian, bicycle, and transit-related activities are high within this section of Museum Road, and so the solution must be sensitive to and consider all travel modes.

The case study includes three problems, each intended to describe one or more aspects of the deliberations toward a workable solution. Where appropriate, Highway Capacity Manual (HCM) analysis procedures are used to illustrate how these applications can be tools to quantify and compare the performance of various alternative treatments to this roadway.

The problems in this case study utilize the HCM analysis procedures for both signalized and unsignalized intersections. After studying this material, you should be able to:

Introduction

Printable Overview, Introduction, and Getting Started

Museum Road is a major internal connector on the University of Florida campus serving a student population of over 46,000 and an employee base of over 11,000. The University of Florida is located in Gainesville, Florida, which has a population of about 100,000. Alachua County, within which Gainesville is located, has a population of over 200,000.

The University of Florida plans to build a major multipurpose parking structure with approximately 400 parking spaces adjacent to the Reitz Union student activity center. The parking structure will have a driveway onto Reitz Union Drive, which provides direct access to Museum Road. The facility will generate significant traffic along Museum Road. The fact that Museum Road has four intersections with major pedestrian, bicycle and bus traffic, presents some interesting and unique characteristics that lend themselves to exploring a variety of capacity analysis techniques.

Discussion:
Take a few minutes to study the University of Florida campus. Note the location of major facilities and how this will affect Museum Road.  When you are ready, click continue below to proceed.

Introduction

The case study area is located near the center of a university campus with about 46,000 students. Museum Road, currently a two-lane roadway with left-turn bays at the intersections, is designed for campus traffic with a 20-mph speed limit and significant pedestrian, bicycle, and bus activity. Exclusive bicycle lanes are provided in both directions.

The four intersections of interest within the limits of the analysis area currently include two traffic-actuated signals, one pretimed signal and a two-way, stop-controlled (TWSC) intersection, with no signal coordination along this urban street. The intersections are closely spaced, about 500 feet between three intersections and about 1,000 feet to the fourth, with very active bus stops near all signalized intersections. Peaking characteristics are also unique, in that pedestrian, bicycle, and bus activity peaks between student classes (several times each weekday). Vehicular traffic tends to peak at the usual morning, noon and afternoon times due to employee work schedules.

Introduction

Exhibit 5-4 shows an aerial photograph of each of the study intersections located along Museum Road that will be analyzed in this case study.

Exhibit 5-5 identifies the locations of bus stops with and without pullovers along roadways in the study area.

Exhibit 5-6 identifies the locations of crosswalks and adjacent parking facilities along roadways in the study area.

Introduction

Consider the situation as described in the above text, figures, and pictures, to come up with a list of issues you feel should be addressed. What is unique about this particular scenario as compared with typical traffic impact study situations? After you have listed the issues, you can move on to Getting Started to see how we can apply HCM procedures to address these issues and provide the necessary information to decision makers on what steps would be best for the overall study area.

Discussion:
Take a few minutes to consider these questions.  When you are ready, click continue below to proceed.

Getting Started

Printable Overview, Introduction, and Getting Started

Several issues will be considered as we begin this case study, including the scope of the analysis, the stakeholders and their perspectives, the overall goals for the analyses, the performance measures to be used to quantify results for comparison, the tools to be used in performing the analyses, the data requirements of these tools, and the technical details that arise from using the HCM methods in this case study.

Scope of the Analysis
The intersections along this section of Museum Road provide unique characteristics that lend themselves to a variety of analysis techniques. The Museum Road facility itself presents some special considerations that must be taken into account in all analyses, due principally to the close intersection spacing and the significant amounts of pedestrian, bicycle, and bus activity.

Getting Started

Stakeholders
There are several stakeholder perspectives involved in the analysis and decisions affecting Museum Road, including:

Getting Started

Goals and Objectives
The driving force behind this study is to provide sufficient information, detailed analyses, and quantitative results to those responsible for deciding the best solution to mitigate the impacts of this new parking structure on Museum Road. Developing alternatives analyses using the HCM to compute performance measures such as capacity, delay, queuing effects, etc., will assist them in making decisions on intersection control, signal timing and coordination, lane configuration improvements, and pedestrian, bicycle and transit operations and safety.

We should also point out that the Manual on Uniform Traffic Control Devices (MUTCD) is commonly used to determine if a signal is warranted, and in most jurisdictions is the legal document used to determine many of the characteristics of a design. However, it is also useful to compare the forecasted operations of an intersection under different control scenarios. The Highway Capacity Manual provides the tools for such an operational analysis.

Getting Started

Performance Measures
The Highway Capacity Manual provides several performance measures for intersections, both signalized and unsignalized. For both types of intersections, the primary measure of effectiveness is control delay. Control delay is directly related to level of service (LOS), a range of levels that categorize performance from the point of view of the driver, or the user of the highway system. Level of service (along with v/c ratio, queue length, and other performance measures) will be used to help determine if the intersection of Museum Road and Reitz Union Drive should be changed from stop sign control to signal control.

Analyses
We must complete several computations to gather the required information on the performance of Museum Road under both stop sign and signal control. For convenience, we've divided the analyses into two problems. We will consider each problem separately. We will also see that each problem consists of several separate computations, using the HCM or other tools, such as macroscopic and microscopic simulation programs.

The following set of case study problems will be analyzed:

Getting Started

Tools
Most of the computations that we conduct in this case study will be with the Highway Capacity Manual, particularly those chapters that deal with intersection. This includes Chapter 16 (Signalized Intersections), and Chapter 17 (Unsignalized Intersections).

For some parts of the analyses, however, and for certain traffic conditions, we might also consider the use of other tools. There is a variety of software tools available that we could use, including macroscopic flow models that consider the progression of traffic platoons from one intersection to the next, and microscopic traffic models that consider both the movement of individual vehicles along an arterial and the details of actuated traffic controller operations.

Getting Started

Data
Three kinds of data are generally needed for traffic analysis. Demand or volume information specifies the turning movement flows (usually in vehicles per hour) at each intersection approach. Intersection geometry includes the number and configuration of lanes at an intersection and along an arterial. Control conditions include information about the traffic signal system, including signal timing and phasing data. For this particular case study, pedestrian, bicycle, transit, and intersection spacing and queuing data are also very important.

Getting Started

Technical Issues
The computational procedures of the Highway Capacity Manual are complex, often including a number of default values or assumptions that need to be understood (and sometimes modified) if the procedures are to be applied correctly to specific problems.

This case study presents, and hopefully clarifies, a number of technical issues that often arise in the application of Chapters 16 and 17 of the HCM. The Exhibit 5-9 lists these issues and identifies which are covered in each of the problems presented as part of this case study.