As I am one of those big rig drivers, in Oregon the rule is 25 MPH hour under the speed limit ..and its our company rule also They MUST be on. SO.... The speed limit is 55 for trucks in Oregon so I am required to use 4ways At 30 MPH or less by Law. Im sorry some of you dont like the law ,but you would not believe the inattentive people that come up on me at high speed and almost hit the rear of my trailers .. and thats with the 4 ways!! I and other truckers do not generally go that slow unless we are climbing a hill .. DO NOT follow me that closely if you cant tell if im braking ( unlikely going up hill ) or moving over ( when the lane ends at the top of the hill) Pass or stay back. Sorry but its just a pet peeve of us slow truckers.
I am on the road ever day ?night and the 4 ways do raise attention to the slow movement .. you would not believe how transfixed most drivers are that they dont realize until too late .. As i said it happens every day to me without fail. 4 ways are meant to signify a hazzard and trust me if your going 25 mph under the speed speed limit you are a Hazzard !!