When a commercial truck stops on a traveled lane or highway shoulder, the warning investigation begins with the reason for the stop, its exact position, traffic direction, road geometry, lighting, visibility, and timeline. Hazard flashers, reflective triangles, fusees, liquid-burning flares, lamps, vehicle conspicuity material, and other warnings should be documented separately because each has a different function and evidentiary history.

A triangle or flare found after impact does not establish when, where, or by whom it was placed, whether it remained visible, or whether its position affected a driver’s opportunity to respond.

Reconstruct the stop before assessing warning placement

  • Truck and trailer identity, dimensions, load, conspicuity material, lamp condition, hazard-flasher operation, and power state
  • Reason for stop, first loss of speed, shoulder entry, final position, lane encroachment, disabled condition, traffic stop, loading, emergency, and restart attempt
  • Roadway, lane, shoulder, median, curve, hillcrest, ramp, work zone, intersection, grade, surface, lighting, weather, traffic flow, and posted controls
  • Driver, passenger, dispatcher, roadside service, law enforcement, tow, witness, 911, app, message, ELD, telematics, camera, and vehicle-data timestamps
  • Warning-device type, quantity, manufacturer, markings, condition, storage location, placement point, orientation, visibility, recovery point, and custodian

Apply the stopped-vehicle rule to the actual location

49 C.F.R. § 392.22 addresses emergency signals for specified commercial motor vehicles stopped on the traveled portion or shoulder of a highway for a cause other than a necessary traffic stop. It distinguishes immediate hazard-flasher use from placement of warning devices and contains general and location-specific placement provisions and exceptions. Identify the road configuration, traffic direction, vehicle position, device type, light conditions, and timing before stating what the section required.

Preserve a scaled scene map rather than estimating placement from memory. Record the truck reference point, lane and shoulder edges, device positions, distances, curve or hillcrest, obstructions, sight line, background lighting, grade, impact point, debris, tire marks, and every location from which a driver or witness observed the stopped vehicle.

Confirm the equipment carried before the stop

49 C.F.R. § 393.95 addresses emergency equipment, including fire extinguishers, spare fuses in specified circumstances, and warning devices for stopped vehicles, with specifications and restrictions that can depend on the vehicle and cargo. Obtain inspection reports, equipment inventories, purchase and replacement records, driver reports, cab and storage photographs, and the physical devices.

49 C.F.R. § 392.7 states that a commercial vehicle may not be driven unless the driver is satisfied that listed equipment is in good working order, including emergency equipment. Determine what was checked, accessible, reported, replaced, or missing rather than inferring the pretrip result from a later scene.

Separate placement from visibility and response

  • Preserve original photographs and video with metadata, exposure, time, camera position, zoom, flash, and any enhancement recorded
  • Test flashers, lamps and reflective devices only under a documented protocol that accounts for impact damage, lost power, repairs, and changed orientation
  • Identify whether devices were struck, dragged, displaced by air wake, moved by responders, picked up, replaced, or absent when the first image was made
  • Reconstruct observer speed, lane, sight line, attention, contrast, glare, traffic, perception, braking, steering, and available escape path
  • Keep rule applicability, equipment availability, placement, visibility, driver response, participant conduct, and collision causation as separate findings

The related truck lighting and conspicuity guide explains how vehicle lamps, wiring, reflective material, environmental visibility, and observation opportunity are examined independently from portable warning-device placement.

Rosensteel Fleishman Car Accident & Injury Lawyers provides information about truck-accident claims involving stopped-vehicle warning evidence. A missing or displaced device should not substitute for a complete event and response analysis.

Sources