According to the American Transportation Research Institute, roadway congestion cost the trucking industry almost $64 billion in 2015.
There are many factors that contribute to trucking slowdowns, but the first step to reducing congestion is to know where problem spots are so transportation agencies can mitigate them.
A persistent gap for these agencies involves truck movements at the local level, the so-called “last mile.” Last mile is a term for the final leg of a roadway network connecting a trunk or main backbone to the end user. For example, from an Interstate to a local distribution center.
Understanding last mile freight movement in detail—“last mile observability”—is essential to making informed planning and investment decisions. However, transportation agencies are often blind to freight flows in the last mile, historically due to data limitations. The data existed, but was too costly to acquire or was proprietary to private trucking companies.
Another difficulty is that freight moves in different ways and times than typical traffic.
“Traffic flows and peak times are different for freight than they are for cars. For instance, freight runs on a 24-hour clock,” said Jeremy Upchurch, FDOT District Freight Coordinator. “If we could see exactly where trucks are traveling, as well as time of day, on specific routes or segments, we could better refine our network.”
Newer applications of GPS and other data are now available and have the potential to provide a clearer understanding of last mile truck movements without relying on commercially sensitive private sector data.
To set the stage for better last mile observability on Florida roads, the Florida Department of Transportation (FDOT) worked with consulting firm CPCS on a research effort to develop strategies, methodologies, and other solutions that incorporate these new resources.
“FDOT is one of the best organizations to test some of these forward-looking solutions,” said Vivek Sakhrani, Global Director of Infrastructure Analytics at CPCS. “The way they’ve been thinking about the problem across the state from a research point of view puts them in a good position.”
The research included analysis of existing FDOT data and tools, a review of literature and national best practices, and consultations with freight data stakeholders, industry vendors, and other transportation agencies around the country.
The analysis revealed two high-level opportunity areas for FDOT to pursue, called freight fluidity and real-time corridors. Neither approach involves building new roads.
“Our basic finding was that FDOT and other DOTs with similar make-up cannot build their way out of this problem,” Sakhrani said. “A lot of the fixes they can make are on the operations side.”
For freight to move most efficiently and cost-effectively, truckers must be able to predict travel times across their routes. Any variation from the prediction, a slowdown or bottleneck, causes “friction” in the trip and adds travel logistics costs like fuel and wages. Also, firms and service providers may penalize carriers for delays or service disruptions.
“If you are a trucker hauling cargo types like fresh-cut flowers from the Miami International Airport into other parts of Florida, you really need to be able to solve the reliability problem,” said Donald Ludlow, Vice President, United States at CPCS.
Freight fluidity is a broad concept and set of approaches that addresses these frictions. Properly done, freight fluidity performance measures can identify where bottlenecks and other issues are and allow agencies to address them.
The research team recommended three applications to help FDOT achieve better last mile freight fluidity:
- Last Mile Flow Maps
- Bottlenecks Analysis
- Travel Time Reliability
“FDOT already collects and maintains a variety of data needed to develop these applications,” Ludlow said. “Including traffic counts, road network and asset data, and freight facility databases, among others.”
Last Mile Flow Maps
As the name indicates, last mile flow maps use GPS waypoint and other data to visualize truck flows through last mile road networks. The maps can be designed to assess a variety of performance measures including truck volume and density as a share of overall traffic, by time of day, and others.
“You can see at a glance which routes truckers prefer and where they might back up,” Upchurch said. “That is invaluable as a basis for freight planning and gives us a starter list of sites for further analysis.”
Bottlenecks are severe traffic chokepoints where demand for roadway use exceeds road capacity. The economic consequences of bottleneck congestion are lost time and productivity as well as increased emissions, fuel use, and noise.
The CPCS team recommended an eight-step process for identifying last mile bottlenecks that utilizes multiple forms of available data. FDOT can use the process to generate bottleneck maps that clearly show problem locations.
Travel Time Reliability Analysis
Travel time reliability (TTR) analysis is an advanced freight fluidity technique that builds on last mile flow maps and bottlenecks analysis. It is about quantifying the value of on-time truck deliveries to identify the most expensive problem segments on last mile routes.
TTR, combined with last mile flow maps and bottlenecks analysis, can provide FDOT a much better basis for making last mile management decisions.
Managing Corridors in Real Time
The second approach recommended by CPCS is real-time corridor management. It involves using multiple innovative technologies and data sources for agencies to sense and respond to freight behavior in real time.
“New traffic data collection and signal network connectivity have made it possible to not only automatically monitor signal performance, but also better connect traffic conditions and signal operations,” Ludlow said.
Real-time corridor management is done largely through more frequent and informed signal retiming and rephasing, as well as freight signal prioritization and dynamic two-way messaging.
“Seeing what is happening in the last mile in real time from a freight perspective is invaluable,” Upchurch said. “Then operators can use the technology at hand to be very responsive and reduce frictions much faster. Traffic moves better and companies save money.”
“FDOT’s efforts in Intelligent Transportation Systems and Arterial Management Programs have positioned it well for the eventual architecture of real-time corridors,” Sakhrani said.
An Integrated Approach
As freight systems and vehicles become more sophisticated and complex, it will be necessary for DOTs to marshal multiple data sources, technologies, and methods to assure the increasing amount of freight on the roads can move efficiently. In its final report, the CPCS team said that FDOT is positioned relatively well for the future, but must continue to pursue new ideas.
“FDOT collects detailed traffic data and updates road network data frequently,” Sakhrani said. “The gap in understanding truck flows over the last mile can be resolved by supplementing their existing efforts with new mobile source data on truck movements. There is no one data source or technique that solves this problem.”
Upchurch said that, while there is significant work to be done, the recommendations in the report are all achievable.
“Real-time corridor management is feasible for us,” he said. “Everything identified in the research is doable.”
Sakhrani sees the effort not as something completely new, but as an evolution of the current system.
“It’s the idea of effective capacity,” he said. “Simply getting more out of existing infrastructure.”
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