Department of Transportation

Truck Weight Monitoring Program

NJDOT maintains Weigh-in Motion (WIM) sites (pdf 1.7m) set up to capture and record axle weights and gross vehicle weights as vehicles drive over the roadway sensors at normal traffic speed. WIM also records axle spacing, speed, and vehicle class according to the number of axles and axle weights.

Most common applications for WIM system and WIM data:

  • infrastructure design and management
  • freight/trade planning and regulation
  • detection and enforcement (Virtual Weigh Station)
  • traffic operation and management
Design Details and Specification

Equivalent Single Axle Load (ESAL) or Load Equivalency Factors (LEFs) is used in the calculation of pavement design. Based on AASHO Road Test results, the most common approach is to convert wheel loads of various magnitudes and repetitions (“mixed traffic”) to an equivalent number of “standard” or “equivalent” loads. The equivalent load commonly used in the U.S. is the 18,000 lb (80 kN) equivalent single axle load (normally designated ESAL). ESAL calculations are dependent upon the pavement type (flexible or rigid) and the pavement structure (structural number for flexible and slab depth for rigid).

Equivalent Single Axle Load (ESAL) Design Factors 2022 (pdf 230k)
Equivalent Single Axle Load (ESAL) Design Factors 2021 (pdf 160k)
Equivalent Single Axle Load (ESAL) Design Factors 2020 (pdf 100k)

Vehicle Travel Information System (VTRIS). The FHWA Office of Highway Policy Information (HPPI) has developed the VTRIS W-Table web site. It is available to all the public. The following reports can be generated online thru the VTRIS database by year of data for each state.

  • W-1 Table: Weigh Station Characteristics
  • W-2 Table: Comparison of Weighed vs. Counted
  • W-3 Table: Average Empty, Loaded, and Cargo Weights
  • W-4 Table: Equivalency Factors
  • W-5 Table: Gross vehicle Weights
  • W-6 Table: Overweight Vehicle Report
  • W-7 Table: Distribution of Overweight Vehicles

WIM sites collect individual vehicle data and can be summarized by volume, speed, directional distribution, lane distribution, date and time of passage. The following sample of special reports by lane, by hourly/daily/weekly or monthly intervals can be generated from raw data. See our Special Reports (zip 2mb)

  • Class by Hour or Day of the Month Report and by Lane or Direction
  • Speed by Hour or by Class Report
  • Gross Vehicle Weight (GVW) by Class Report
  • Weight Violations by Hour or Day by Class Report
  • Single/Tandem/Tridem Axle weights Report

Last updated date: April 11, 2024 8:12 AM