We all know those signs do little, but it is even deeper to keep drivers from using them. I handle Energy Industry (and Marine) insurance claims. Everything from big deep water projects, subsea pipelines and equipment. . .to over the road drilling and fracking vehicles. Some years ago, I did one up in Michigan where a frac support truck ran off of the road because he used his Jake brake and underestimated the effect. Of course the company had a policy of no Jake brake use. . . guess they should have disabled it. . . .