Springtime PSA: This is what you look like in the mirror of a Tractor-Trailer without your lights on in the rain. - Album on Imgur
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Springtime PSA: This is what you look like in the mirror of a Tractor-Trailer without your lights on in the rain.
For the love of God, turn your lights on.
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I'd be willing to bet that the vast majority of people here are fully aware of this, but it might be something you'd like to show any novice drivers in your household.