dewey02 wrote:
There is a very steep uphill grade on an interstate near where I live. It also has a 3rd truck lane. It is VERY common to see trucks straining to get up that hill and going pretty slowly, and most of them have their 4 way flashers on.
I find that warning helpful, because it tells any oncoming drivers that the truck is going very slowly and to be cautious.
I can't tell you whether it is an illegal use in this situation in my state or not, but I see it happening on almost a daily basis, and I personally think it is a good safety practice.
Here's a link to every state and what they say about using the hazard warning flashers while driving. A few seem to say it is illegal while moving. Most say it is illegal except to indicate a traffic hazard (going very slowly up hill may be a reason, I would guess), and some just allow it for any reason.
http://drivinglaws.aaa.com/tag/hazard-light-use/
Good link! And it looks like hazards in your state are legal for what you describe.
South Carolina seems to have the most detailed description of use: "Hazard lights may be used while driving for the purpose of warning the operators of other vehicles of the presence of a vehicular traffic hazard requiring the exercise of unusual care in approaching, overtaking or passing."
As to the pickup truck in the original post, I have no idea. I would probably just stay far away from it.
On a semi-related side note: In Connecticut, you can't just put a separate yellow/orange flashing light on your vehicle, you need a permit for that. All those utility trucks, repair trucks, even town and state snowplows have to have a permit in their glove box for the flashing / strobing yellow lights. If the yellow light is a normal factory light on the vehicle (like hazards, or "4-ways" as some call them), you don't need a permit. Realistically, most small contractor snowplow operators don't have the yellow light permit, and the vast majority of police won't ask for it in the middle of a snowstorm.