Russell H Henk

Developing an Index of Transit Service Availability

The procedures and results associated with the development of an index of transit service availability are summarized. This index uses the factors that most effectively quantify the availability of public transit service (both bus and rail) in an urban area at a macroscopic planning level. The factors that are included in the index are based on FTA Section 15 data and information from the 1990 census. The development of the index involved the application of more than 30 prospective measures of transit service availability to 228 urban area transit systems throughout the United States. The index uses three measures that quantify transit service coverage, frequency of transit service, and transit system capacity. The index is designed to serve as a planning tool and was specifically developed to facilitate the comparison of transit service availability between urban areas with similar demographics and allow transit systems to examine service availability over time. The index is not intended for use in assessing transit system efficiency or performance.

Dynamic Traffic Assignment Evaluation of Hurricane Evacuation Strategies for the Houston-Galveston, Texas, Region

The Houston–Galveston, Texas, region has experienced several major hurricanes in recent years. During the evacuation for Hurricane Rita in 2005, the Texas Department of Transportation (DOT) decided to implement contraflow operations on I-45 to relieve massive evacuee congestion departing Houston to the north. The decision to implement contraflow was a difficult one because it involved multiple jurisdictions and required extensive coordination of manpower and resources from various entities. After the Hurricane Rita experience, the Texas DOT implemented a new strategy, referred to as “evaculane,” in which evacuation traffic could use the outside paved shoulder as a traveling lane when an evacuation was under way and evaculane signing beacons were activated. The objective is to increase capacity along key evacuation routes while avoiding the need for full-scale contraflow operation whenever possible. The evaculane on I-10 was successfully put into use during the Hurricane Ike evacuation in 2008. With the widening and completion of evaculanes on I-10 and US-290 as well as a partial contraflow plan for the I-45 corridor, the Texas DOT sponsored a study to develop a decision support tool to help determine whether these strategies would adequately handle the evacuation demand for various Houston–Galveston region evacuation scenarios. This paper describes the quantitative assessment of the performance of alternative evacuation strategies using a dynamic traffic assignment model, DynusT. The evaluation results indicated the evaculanes on I-10 and US-290 can sufficiently handle high evacuation demand on both routes without contraflow operation. In addition, a partial contraflow plan for I-45 was shown to provide sufficient capacity to handle high evacuation demand in lieu of full-scale contraflow operation.

DEVELOPMENT OF ACCESS SPACING GUIDELINES FOR NONFREEWAY WEAVING ENVIRONMENTS

Access on the frontage road in close proximity to exit ramp terminals can amplify the amount and severity of weaving that occurs and can lead to operational and safety problems on the frontage road. Research activities directed at evaluating the operation of frontage roads with unsignalized marginal access located at different distances from exit ramp terminal points and developing guidelines for appropriate spacing under these conditions are summarized here. The basic research approach consisted of (a) analyzing accident data; (b) observing operations in the field to identify distances required to safely make weaving maneuvers; and (c) developing an analytical model to predict the density of the weaving section on the frontage road as a function of frontage road volume, exit ramp volume, total driveway volume, frontage road configuration, and exit ramp to access spacing. The model was developed from the results of a computer simulation (using CORSIM) that was calibrated with field data from several frontage road sites in Texas. Results of the accident and weaving (field observation) analyses were used to develop a recommended minimum distance of 140 m between exit ramp terminal points and the nearest frontage road access; the analytical model was used to develop desirable spacing distances ranging from 140 to 300 m. The model was also used to identify possible level-of-service boundaries that can be used to assess the quality of service provided on a particular section of frontage road.

INNOVATIVE DATA COLLECTION TECHNIQUES FOR ROADSIDE ORIGIN-DESTINATION SURVEYS

Described are the results of a pilot application intended to automate the data collection and data reduction phases of roadside origin-destination (O-D) studies. Most techniques used to obtain O-D data are quite labor intensive, during both the data collection and the data reduction phase. Frequently, they result in extensive data quality checks and long turnaround periods between the data collection work and the submittal of the corresponding survey report. The application described automates the data collection and data reduction phases by using portable, handheld data collection devices. These devices can be connected to a desktop or laptop computer to transfer the O-D data to a depository database. Included are a brief background discussion, a description of the hardware and software used and the design and development of O-D applications, a description of two applications of the handheld data collection devices, and a list of lessons learned.

INNOVATIVE COMMUTER SURVEYING TECHNIQUES USED IN ADVANCED TRANSPORTATION MANAGEMENT SYSTEM EVALUATION

Procedures and results associated with a unique approach for conducting commuter surveys in San Antonio, Texas, are presented. This approach was specifically developed in association with a before-and-after evaluation of Phase II of San Antonio’s advanced transportation management system (ATMS), known as TransGuide. The primary purpose of the surveys is to identify user understanding and utilization of ATMS components. The surveying approach used a geographic information system (GIS) application that would identify the appropriate group to survey on the basis of the location of the incident and the route information supplied by the survey panelists. This automated approach reduced the number of nonapplicable surveys that were distributed, was easy to use, and could identify the survey panel very quickly. Using the results of the GIS application, surveys were distributed in both paper and electronic formats. The electronic method consisted of sending via electronic mail a request to complete a survey that would guide the respondent to an on-line survey that they could use to answer the questions. The electronic survey significantly reduced the labor and materials costs associated with distributing the survey. The preliminary response rates indicate that, at a minimum, the electronic survey will provide the same response rate with a reduction in cost. Although issues concerning sample bias must be considered, the electronic survey method has the potential to be more effective and more efficient than most of the other surveying techniques commonly used in current practice.