This case study is the third of five, performed by the project team in order to validate the approaches to travel time reliability monitoring described in the Travel Time Reliability Monitoring Guidebook. The goal of each case study is to illustrate how agencies apply best practices for: monitoring system deployment; travel time reliability calculations; and agency use and analysis of the system. To accomplish this goal, the team is implementing prototype travel time reliability monitoring systems at each of the five sites. These systems take in sensor data from a variety of transportation networks, process this data inside a large data warehouse, and generate reports on travel time reliability for agencies to help them better operate and plan their transportation systems. This case study consists of the following sections:
- Monitoring System
- Methodological Advancement
- Use Case Analysis
- Privacy Considerations
- Lessons Learned
This monitoring system description section details the reasons for selecting the Lake Tahoe region as a case study and provides an overview of the region. It briefly summarizes agency monitoring practices, discusses the existing sensor network, and describes the software system that the team used to analyze the use cases. Specifically, it describes the steps and tasks that the research team completed in order to transfer data from the data collection systems into a travel time reliability monitoring system.
The section concerning methodological experiments describes the manner in which different types of filtering techniques might be applied at different stages of the analytical process to further refine the travel times estimates generated from Bluetoothbased datasets.
Use cases are less theoretical, and more site specific. The first two use cases assess the impact of detector network configuration on the data ultimately available for use by travel time reliability monitoring systems. The third use case attempts to quantify the impact of adverse weather and demand–related conditions on travel time reliability using data derived from the Bluetooth and electronic toll collection-based systems deployed in rural areas as part of this case study.
The section on Privacy Considerations addresses the challenges associated with collecting data using toll tag and Bluetooth-based technologies in a manner that respects the privacy of the individuals from whom the data is being collected.
Lessons Learned summarizes the lessons learned during this case study, with regard to all aspects of travel time reliability monitoring: sensor systems, software systems, calculation methodology, and use. These lessons learned will be integrated into the final guidebook for practitioners.
Operations Area of Practice
- Detection Systems
- Communicating Reliability Information
- SHRP2 Tools
- System Performance Definition, Monitoring and Reporting
- Travel Demand Forecasting
Organizational Capability Element
- Reliability Predictive Models
- Case Studies & Lessons Learned
Role in Organization
- Associate Engineer
- CEO / GM / Commissioner
- Director / Program Manager
- Manager / First Line Supervisor
- Principal Engineer
- Senior Engineer
- Senior Manager
- Transit Professional
- Transportation Planner
- SHRP2 Program
Lake Tahoe Case Study Validation.pdf (1.77 MB)