This traffic sign with its sign support structure were used in NCHRP 350 crashworthiness testing. This configuration did not pass the test. Subsequently a modified version without the advisory speed plate and with modifications to the sign support structure was developed and successfully tested.
This image was copied from wikipedia:en. The original description was:
Traffic Sign: Road Work Ahead
This is an example of a dangerous sign. In a side-impact crash test the advisory plate (it says 62.5 MPH) and the edge of the sign penetrated the windshield and roof of the test car. A safer sign would have stiffer uprights, no advisory plate and the warning light would be moved to the point of the sign to spread the impact force.
Transwiki approved by: w:en:User:Dmcdevit This image was copied from wikipedia:en. The original description was: Traffic Sign: Road Work Ahead This is an example of a dangerous sign. In a side-impact crash test the advisory plate (it says 625 MPH,