The Office of Defects Investigation (ODI) opened this Defect Petition (DP) assessment in response to a defect petition received from owners of a 2015 Volvo VNL 780 tractor.Prior to submitting the letter the owners had submitted two Vehicle Owner Questionnaires (VOQ).Their concerns included: cab sway, cab alignment , and loss of control.The petitioners further allege that due to a failure of the suspension system caused by cab misalignment one of them sustained a back injury while seated at the work station in the sleeper berth while traveling.The office received a total of six (6) complaints (1 via telephone) related to ride quality on 2013 -2016 Volvo VNL vehicles.Two (2) of the complaints were filed by the petitioners.Of the five (5) unique complaints, three (3) were received during the course of this evaluation.During this evaluation, the Owner/Operators Independent Drivers Association (OOIDA) published an article in their magazine, Land Line, prompting the additional two reports.One owner reported owning three Volvo trucks, all of which had a tendency to sway and lean, yet he preferred the ride over other manufacturers peer vehicles.ODI sent an Information Request (IR) letter to Volvo asking about the three concerns identified in the petition.The response indicated Volvo's cab air ride design has been in use since 2005.When evaluating each of the three concerns raised by the petitioners, ODI found that the complaint and warranty data did not establish existence of a defect trend for cab sway or loss of control.There were no reported injuries or loss of control events and less than 0.02% of the population had a cab sway concern.The majority of claims and complaints received involved cab alignment.The 2015 MY did stand out from the other MYs with over 1% of the 2015 population reporting cab alignment issues.This may indicate there is a defect in the design or production of the cab mounting, however there was no indication it created a safety risk.ODI test drove th