In The News
Trucking must wait longer to get size-and-weight answers as DOT asks for more data
WASHINGTON — The trucking industry is going to have to wait a little longer to get a definitive answer from the federal government with respect to its opinion on whether larger and heavier trucks should be allowed on the nation's highways.
The U.S. Department of Transportation said in a report to Congress April 14 that after studying the issue, reviewing the data and listening to public comments, that additional data analysis is necessary to "fully understand the impacts of heavier and larger trucks on the transportation system."
Congress mandated the study when it passed MAP-21, the previous transportation bill, in June 29, 2012.
The DOT said it organized the study around five technical areas:
- Highway safety and truck crash rates, vehicle performance (stability and control), and inspection and violation patterns
- Shifts in goods movement among truck types and between modes
- Pavement service life
- Highway bridge performance, and
- Truck size-and-weight enforcement programs.
But apparently the DOT couldn't get comfortable with what it found enough to draw any solid conclusions, saying that "... in each of the study areas, there are data gaps and insufficiencies in the models that make it highly improper to extrapolate the results from each of the five technical areas across the national system."
The DOT said it believed that the data limitations were so profound that the results could not accurately be extrapolated to confidently predict national impacts.
"Subsequent public input and peer review has not altered that view," the report said. "As such, the department stresses that no changes in the relevant federal truck size and weight laws and regulations should be made until these limitations are overcome. Despite recent Congressional action approving additional size and weight exceptions and waivers on a piecemeal and nationwide basis, DOT recommends a thoughtful approach to future policy-making.
The report said to make a genuine, measurable improvement in the knowledge needed for these study areas, a more robust study effort should start with the design of a research program that can identify the areas, mechanisms, and practices needed to establish new data sets and models to advance the state of practice.
"This research plan could be developed by an expert panel, perhaps convened by the NAS, and should include a realistic estimation of timelines and costs," the report said.
Recommended areas of research included:
Truck Weight Data in Crash Databases. — The report said a consistent theme in past research on size and weight issues has been the limitations of crash and exposure data. Most crash data systems are inadequate in terms of allowing precise identification of longer or heavier trucks. No state crash data system includes the operating weight of trucks at the time of the crash.
Truck Configuration Data in Crash Databases. — The lack of data elements in most state crash databases that would identify the configuration of a truck limits crash analysis and the development of crash estimates. Data elements in state crash databases to identify the truck configuration are needed (count of trailers, a count of total axles, and the length of each trailer for combination vehicles involved in crashes).
Weigh-In-Motion (WIM) Coverage. — The WIM equipment can be used to collect data on such factors as vehicle and axle weights, axle spacing, speed, and vehicle class. The WIM data was essential for conducting an assessment of crash information among trucks by type and various gross vehicle weights. The WIM data was predominately available for the Interstate System but was very limited for other National Highway System roadways.
Longitudinal Barriers. — Longitudinal barriers for use in federally funded projects are currently evaluated based on a series of crash tests where the maximum GVW is 80,000 pounds for a tractor-semitrailer combination. An analytical framework and related tools are needed to measure the impacts heavy trucks (trucks weighing more than 80,000 pounds) would have on roadway barriers.
Motor Carrier Management Information System. — The truck configurations examined in this study were limited to those available within the MCMIS inspection file. Each inspection included information about the type and number of vehicle units as well as the GVW. Note that the gross combined vehicle weight field is filled in by the field inspector and may include the gross vehicle manufacturers' weight rating, the weight of the load per the bill-of-lading, or an actual measured weight if the truck was weighed at time of inspection. Quality control and assurance of data input by field inspectors in Gross Vehicle/Combination Weight field in the MCMIS is needed.
Annual Certifications and State Enforcement Plans. — Much of the available cost data reflects the allocation of resources for both truck size and weight and commercial vehicle safety enforcement. The costs reported by States reflect resources (e.g., personnel, facilities) directed at truck size and weight enforcement and truck safety enforcement. Approaches and protocols are needed to identify truck weight enforcement program costs separately from overall truck safety enforcement costs. In addition, requiring data submitted by the States in Annual Certifications and State Enforcement Plans to separate the person-hours or program costs attributed specifically to weighing trucks would be beneficial to future analysis.
"In many ways, this study produced more questions than it sought to answer. Another study effort, with more time and more money, would not at this point yield more reliable results," the report concluded. "To make a genuine, measurable improvement in the knowledge needed for these study areas, a more robust study effort should start with the design of a research program that can establish data sources and models to advance the state of practice. Not all of this is within the purview or capacity of DOT. Even recent gains in long-term reauthorization of transportation programs does not sufficiently advance the state of research and data to enable us to say when or even whether we will be in a position to collect and analyze better data and apply it to improved policy determinations and regulatory strategies."
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