What happened
Arizona Department of Public Safety stopped a tractor-trailer in Chandler on Sept. 18 after a blown tire was producing many sparks and the driver reportedly did not realize it. Inspectors found several trailer tires that were bald or worn into their internal components. Authorities also said the driver’s CDL was not valid. Both the vehicle and driver were placed out of service. Land Line Media reported the incident on Sept. 25; its report did not state why the CDL was invalid or allege that the oversize load lacked a permit.
What drivers should do
Federal tire standards in 49 CFR 393.75 prohibit operation with exposed body ply or belt material, tread or sidewall separation, a flat or audible leak, or a cut exposing ply or belt material. Front tires on a bus, truck or truck tractor must have at least 4/32 inch tread depth in a major groove; other tires must have at least 2/32 inch. The rule also requires adequate cold inflation pressure for the load being carried. Meeting the tread minimum does not make a tire safe when another prohibited defect is present.
Why this matters to our community
Before dispatch, measure tread with a gauge rather than estimating by sight; check every steer, drive and trailer tire for exposed cord, separation, cuts, bulges, leaks, uneven wear and correct pressure. Record each defect on the driver vehicle inspection report and do not move the combination until an unsafe condition is repaired. The carrier should also verify the driver’s current license class, endorsements, restrictions, expiration and medical-certification status before assigning the trip. If a tire fails or produces smoke or sparks on the road, slow down without abrupt steering, move to a safe location if possible, activate hazard flashers, secure the scene under company procedure and contact emergency services when fire or immediate danger exists. Useful English terms include tread depth, major tread groove, exposed cord, sidewall separation, audible leak, out of service, license status and repair verification.