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Weigh-in-Motion

The Weigh-in-Motion (WIM) program provides the Truck Weight Monitoring portion of the State's Traffic Monitoring System for Highways. Of all the traffic monitoring activities, WIM requires the most sophisticated data collection sensors; the most controlled operating environment (strong, smooth, and level pavement in good condition), and the most effort to set up and calibrate.

WIM Sensors
Left: Port of Anchorage Virtual Weigh-in-Motion (WIM) site. Maryann Dierckman, Alaska DOT&PF
Right: Tok, Weigh-in-Motion (WIM) traffic data sensors in the pavement (bending plate and loop). Mistee Vinzant, Alaska DOT&PF

WIM systems are designed to measure the vertical forces applied by the truck axles to sensors in the roadway, thereby providing an estimate of the axle weights. The data are collected at each site as a vehicle passes over the WIM site. Vehicles can drive through at mainline speeds and do not have to stop like they do at most traditional weigh stations.

WIM data is used for federal reporting and secondary weight enforcement which are then uploaded to the traffic system. It is a web-based system which coordinates statewide data collection and analyses of vehicle weight, length, classification, counts, and speed. Due to the nature of the confidential data, it is only available to authorized users within DOT and DOT&PF Division of Measurement Standards & Commercial Vehicle Enforcement (MS&CVE).

 

A WIM Station provides the following data:

  • vehicle gross weight*

  • vehicle weight by axle*

  • vehicle speed by lane and direction

  • vehicle length*

  • vehicle classification*

  • vehicle volume

  • vehicle speed

  • time stamp

  • if vehicle is overweight by vehicle classification or axle

  • location by lane and direction

* data also collected at traditional weigh stations.

 

WIM data provides information for the following:

  • for secondary weight enforcement by the DOT&PF Division of Measurement Standards & Commercial Vehicle Enforcement (MS&CVE)

  • to calculate Equivalent Single Axle Load (ESAL) for pavement and bridge design

  • to calculate Average Annual Daily Traffic (AADT) volumes and generate vehicle classification reports

  • to meet federal reporting requirements

  • to upload data into Federal Highway Administration (FHWA) Travel Monitoring Analysis Software (TMAS)

  • to report gross vehicle weight by lane and direction

  • to report vehicle classification by lane and direction

  • to report vehicle count by lane and direction

  • to upload data into the State’s Traffic Monitoring System called Alaska Traffic Server

 

Alaska WIM Sites

Anchorage Area:

  • Minnesota Drive

  • Tudor Road

  • Seward Highway at 76th Avenue Ramp

  • Ocean Dock Road (Port of Anchorage)

  • Glenn Highway, Milepost 9*

Other Areas:

  • Glenn Highway, Milepost 53 (Palmer)

  • Steese Highway, Milepost 10 (Fox)

  • Alaska Highway, Milepost 1310 (Tok)

  • Sterling Highway (Soldotna)

*co-located with weigh station.

 

Weigh Stations

Weigh stations are also part of the State's Traffic Monitoring System for Highways. Weigh stations are equipped with scales, some of which permit the trucks to continue moving while being weighed, while older scales require the trucks to stop. DOT&PF employs various scale types from single axle scales to multi-axle sets, depending on the configuration of the weigh station. Signal lights indicate if the driver should pull over for additional inspection or if the driver can return to the highway. Each weigh station gathers specific information for every vehicle that passes through. Currently, the following weigh stations are in Alaska:

  • Parks Highway, Milepost 313 (Ester)

  • Steese Highway, Milepost 11 (Fox)

  • Glenn Highway, Milepost 9

  • Seward Highway, Milepost 9

  • Sterling Highway, Milepost 46

  • Alaska Highway, Milepost 82 (Tok)

  • Richardson Highway, Milepost 3 (Valdez)

 

A weigh station provides the following data:

  • vehicle weight by axle

  • gross vehicle weight

  • vehicle classification

  • Vehicle length

Weigh station data is used:

  • for weight enforcement by the DOT&PF MS&CVE

  • to calculate Equivalaent Axle Load (EAL) for pavement and bridge design

  • to meet federal reporting requirements

  • to meet state permitting requirements

Alaska weigh stations are managed by the Division of Measurement Standards & Commercial Vehical Enforcement.

For questions regarding WIM data and reporting, contact the HPMS Manager:
Transportation Data Contacts

For questions regarding weigh station permits and operations:
DOT&PF MS&CVE Contacts