That&#x27;s a good question.<p>My <i>guess</i> is that either the driver&#x27;s vision will be quickly impaired or his&#x2F;her eyes will quickly start hurting. In that case, the driver will quickly know something is wrong even if he&#x2F;she may not know it&#x27;s an attack.<p>I&#x27;m no expert on laser safety or human biology, so I left a question on biology SE: <a href="http:&#x2F;&#x2F;biology.stackexchange.com&#x2F;questions&#x2F;38603&#x2F;how-quickly-can-lasers-of-various-wavelengths-and-powers-impair-human-vision-or" rel="nofollow">http:&#x2F;&#x2F;biology.stackexchange.com&#x2F;questions&#x2F;38603&#x2F;how-quickly...</a><p>Hopefully somebody can give an answer.<p>And if the driver experiences no symptom, then the attack is just ineffective.