Common Questions / Car Accidents
How do you prove the other driver was drowsy or fell asleep?
There is no breathalyzer for exhaustion, so fatigue is proven by reconstruction: the crash with no braking, the drift across the line, the work schedule that made sleep impossible, the phone that was active until 3 a.m. Fatigue cases are circumstantial cases, and circumstantial cases are built, not found.
The crash signature of a sleeping brain
Fatigue crashes announce themselves in the physical evidence before anyone says a word: no skid marks, no braking in the event data, no evasive steering, a vehicle that drifted across a centerline or departed the road on a gentle curve at full speed, often in the early morning hours or the mid-afternoon trough when human alertness bottoms out. Drivers rarely confess to sleeping, the standard account is the sudden swerve, the animal, the mystery vehicle, but the absence of reaction is itself the testimony, because an awake driver does something, and this one did nothing.
Building the sleep case from the outside in
The rest is investigation. The driver's day is reconstructed through discovery: the employment records showing the double shift or the overnight rotation, the second job, the commute stacked on both, the phone records active into the small hours and, tellingly, silent in the minutes before impact, the receipts and toll tags mapping a drive far longer than rest allows, the medical history where untreated sleep apnea lives. None of these alone proves sleep; together they let a jury conclude that an exhausted person chose to aim a vehicle down a public road anyway, which is the negligence, the choice to drive impaired by fatigue, not the biology of the final seconds. Texas needs no special statute for this; ordinary negligence law has always condemned driving in a condition that makes safe driving impossible.
The commercial version, where the proof is federal
When the drowsy driver is professional, the case sharpens: the hours-of-service rules covered on the trucking pages exist precisely because fatigue kills, the electronic logs record the driving windows to the minute, and a carrier whose logs show violations, or whose dispatch records show schedules only a falsified log could satisfy, has converted a fatigue argument into a regulatory one, with the company's own paperwork as the exhibit and its scheduling culture as the road to gross-negligence exposure. Fatigue is the impairment the industry pretends is a work ethic, and the documents usually know better.
If the story is I don't know what happened
That sentence, from the driver who hit you, is where a fatigue investigation begins, and it begins fast, before the phone data cycles and the schedules are rewritten. Silver Key Law builds these cases from the evidence outward, and the consultation is free.
Injured in Arizona? Some rules on this page are Texas-specific. Arizona differs on points that change outcomes, including pure comparative fault and government-claim deadlines. See our Arizona answers or call (888) 508-6967.
Related: FMCSA & Hours of Service · Proving Texting & Distraction · Submit Your Case · All Common Questions
This page is general information about Texas law, not legal advice about your specific situation. Deadlines and outcomes depend on facts; talk to a lawyer about yours.
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