Preliminary Assessment of Overweight Mainline Vehicles
- ORNL
The Federal Motor Carrier Safety Administration requested information regarding overweight and oversized vehicle traffic entering inspection stations (ISs) in order to develop strategies for future research efforts and possibly help guide regulatory issues involving overweight commercial motor vehicles (CMVs). For a period of one month, inspection stations in Knox County and Greene County, Tennessee, recorded overweight and oversized vehicles that entered these ISs. During this period, 435 CMVs were recorded using an electronic form filled out by enforcement personnel at the IS. Of the 435 CMVs recorded, 381 had weight information documented with them. The majority (52.2%) of the vehicles recorded were five-axle combination vehicles, and 50.6% of all the vehicles were permitted to operate above the legal weight limit in Tennessee, which is 80,000 lb for vehicles with five or more axles. Only 16.8% of the CMVs recorded were overweight gross (11.5% of permitted vehicles) and 54.1% were overweight on an axle group. The low percentage of overweight gross CMVs was because only 45 of the vehicles over 80,000 lb. were not permitted. On average, axles that were overweight were 2,000 lb. over the legal limit for an axle or group of axles. Of the vehicles recorded, 172 vehicles were given a North American Standard (NAS) inspection during the assessment. Of those, 69% of the inspections were driver-only inspections (Level III) and only 25% of the inspections had a vehicle component (such as a Level I or Level II). The remaining 6% of inspections did not have valid Aspen numbers; the type of was inspection unknown. Data collected on the types of trailers of each vehicle showed that about half of the recorded CMVs could realistically be given a Level I (full vehicle and driver) inspection; this estimate was solely based on trailer type. Enforcement personnel at ISs without an inspection pit have difficulty fully inspecting certain vehicles due to low clearance below the trailer. Because of this, overweight and oversized vehicles were normally only given a Level III (driver) inspection; thus, little is known about the safety of these vehicles. The out-of-service (OOS) rate of all the inspected vehicles (driver and vehicle inspections) was 18.6%, while the OOS rate for vehicle inspections (Level I and II) was 52.4%. Future work will focus on performing Level I inspections on five-axle combination tractor-trailers and the types of violations that overweight vehicles may have. This research will be conducted in Tennessee and possibly in other states as well.
- Research Organization:
- Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
- Sponsoring Organization:
- Work for Others (WFO)
- DOE Contract Number:
- DE-AC05-00OR22725
- OSTI ID:
- 1030625
- Report Number(s):
- ORNL/TM-2011/463; 400407000; TRN: US201201%%324
- Country of Publication:
- United States
- Language:
- English
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