HD7A - Virginia Commuter Study -- Martinsville Case Study

  • Published: 1983
  • Author: Department of Highways and Transportation
  • Enabling Authority: House Joint Resolution 150 (Regular Session, 1980)

Executive Summary:
The purpose of the Virginia Commuting Study is to assess the feasibility of alternative transportation modes for commuters working in metropolitan centers, while residing in outlying communities. The study was prompted by the General Assembly's concern over the problems facing such commuters in a state and national climate of declining transportation revenues, high costs of building and operating transportation facilities, and an uncertain energy future. Of particular concern is the desire to identify more cost- and energy-efficient modal alternatives to the single-occupant auto, which characterizes much of today's commuting in Virginia.

Study Approach

The approach to this study has followed three broad phases:

1. The identification of problems and issues associated with commuting in Virginia (with an emphasis upon longer-distance commuting from outlying suburbs and exurban areas) and the development of policy, program, and legislative options to address these issues.

2. The identification of available modal options for such commuting (as drawn from national experience) and the development of a planning methodology through which the applicability of these options can be determined for urban areas in Virginia.

3. A detailed analysis of three case study areas – Northern Virginia, Roanoke, and Martinsville – in which the methodology developed in the second phase will be applied to determine the viability of various commuter options in these areas. The case study areas were chosen by the Virginia Department of Highways and Transportation (VDH&T) to provide a cross-section of urban area size and commuting problems that is somewhat representative of commuting conditions across the state.

An important feature of the study is the definition in Phase I of three future scenarios for commuter transportation in the 1980s and beyond, which reflect the uncertainties that exist with regard to energy availability and costs and financial resources for transportation improvements. The viability of alternative transportation actions in the case study areas (Phase 3) and alternative policy and program actions (Phase I) is considered within the context of the scenarios to define actions which appear appropriate under any of the scenarios (and thus, represent high-priority actions for implementation).

Organization of this Report

This report documents one of the three case studies in Phase 3. Other reports describe the analyses and results of Phase I (Commuting Problems, Issues, and Policy/Program Response) and Phase 2 (A Methodology for Evaluating Commuter Travel Options in Virginia Cities). An Executive Summary provides an overview of the entire study and highlights principal conclusions and recommendations.

The presentation of case study analyses and conclusions basically follows the principal steps of the planning methodology that is detailed in the Phase 2 report. The case studies have the dual objectives of identifying actions that can be taken to improve commuting in each area and demonstrating the use of the planning methodology in a variety of commuting environments. The second objective requires that each step of the analysis be documented in detail so that subsequent users of the methodology can achieve maximum benefit from application in the case studies. Thus, the report contains more extensive tables, sample calculations, and description of assumptions than would ordinarily be found in a typical project feasibility study.

While each case study report follows the general outline of the major steps in the planning methodology, there are important differences in the way in which material is presented and in the level and type of analysis for each case study. This results primarily from the vast differences in commuting conditions between a large urban region such as Northern Virginia, that is part of an even larger metropolitan area, and a smaller, free-standing urban area, such as Martinsville. The types and level of problems in two such contrasting areas obviously demand different planning and analytical techniques, and the resulting transportation solutions are likely to be quite different in form, cost, and impact.

Finally, some of the variation in the case study discussions is the result of different analysts working on each area. While there was extensive communication between the three principal analysts during the study, each was given considerable flexibility in adapting and applying the basic methodology to conditions in his respective study areas. This had the benefit of producing three fairly independent tests of the planning methodology, reflecting not only differences among study areas, but differences in interpretation of the methodology, as well.

Definitions

In order to ensure that the application of the methodology is fully understood, some important terms and concepts will be defined in this section. Although explained in the Methodology Report, compilation of some of the more frequently used terms and concepts will enable ready reference for the analyst.

• Travel Market - A travel market is simply any group of travelers sharing a chosen set of common characteristics. The most important travel market in the Virginia Commuter Study is comprised of long-distance commuters, living in a specific corridor and commuting to the central area of a city. Thus, to the degree possible, information and analysis concerning commuter travel patterns is most helpful if it is on a corridor specific basis. Figure 3.1 illustrates different types of travel markets.

• Modal Options - Modal options are the different ways by which commuters can travel to work. Mode split is calculated for four modal options:

1. Single Occupant Auto
2. Carpool (two through six persons)
3. Vanpool/Buspool (seven or more persons)
4. Transit (where available or planned)

Transit includes all submodes of transit except local bus service, which is not applicable to long distance commute trips. These submodes are Express Bus, HOV Facility/Light Rail, Rapid Rail, and Commuter Rail. Although it is rare, there may be occasions where more than one transit submode is available or planned in a corridor. In these instances, the submode which is estimated by the methodology to generate the highest mode share should be chosen to represent the entire transit mode share. Transit submodes should not be added together as the methodology was developed with the assumption of no competition among transit submodes. The hierarchy of modal options is shown in Figure 3.2.

• Modal Summary Tables - The modal summary tables (contained in the methodology report) are tables used to calculate mode shares for each of the four modes. Each table contains a basic mode share plus factors to be applied to the basic mode share, dependent upon characteristics of the corridor under examination. The basic mode share is the proportion of commuters expected to use a mode with the assumption that the travel market under consideration is typical in regards to trip length, income, and other socioeconomic variables. The basic mode share is different for different-sized urban areas and has a low, normal, and high value. In the vast majority of instances, the normal value should be used. The low or high value should be used only when the area has characteristics that affect commuter travel which are radically different from similar-sized urban areas. The modal summary tables used in the Martinsville case study, "Carpool-Small Urban Area" and "Vanpool/Buspool-Small Urban Area" are reproduced as Tables 3.1 and 3.2. The analyst should refer to Part 2 of the Methodology Report for further detail.

• Socioeconomic Adjustment Factors - These factors (contained on the modal summary tables) reflect the propensity of certain commuter attributes to influence the use of a particular mode. A factor of greater than 1.000 indicates that commuters who exhibit the characteristic are more likely to use the mode than the norm. A factor of less than 1.000 indicates that commuters who exhibit the characteristic are less likely to use the mode than the norm.

• Ridesharing Assistance Factors - These factors (at the bottom of the modal summary tables) serve a similar function as the socioeconomic adjustment factors. They indicate the expected effects on mode share by the type of ridesharing assistance which is provided.

Sketch Planning Precision

A final consideration of paramount importance is the precision and use of the various quantitative estimates developed during the application of the methodology. The case study is designed to both test the reasonableness of the conclusions which arise from the methodology and to provide a step-by-step analysis for future users of the methodology. This latter purpose results in the inclusion of very detailed numerical values in the analysis. Owing to the broad-based nature of sketch planning, in many instances these values are not precise, but represent interim steps necessary to reach more accurate conclusions in later steps. The value of sketch planning is at the aggregate level and in allowing relatively quick analysis and comparison of alternative actions. Disaggregated values and absolute quantities should be viewed as reasonable approximations only.

To assist the analyst, a Conclusions section has been included, where appropriate, to bring together estimates and judgements which are valid within the sketch planning context. Any numerical values not included in these sections should be regarded as interim steps of unknown precision.