Have you REALLY tried?
World War 2 poster. Most of us are familiar with the "When you ride alone you ride with Hitler" car club poster. This one reminds people that millions of GIs are sacrificing much more than the car pooler who must put up with the relative inconvenience of car sharing.
More fascinating WW2 propoganda posters at New Hampshire State Library. I'm almost certain these posters are in the public domain.
I've added this to the "PAIN AT THE PUMP" pool to remind folks that some people are indeed experiencing real physical pain to keep the oil flowing. These men and women go into harm's way losing limbs and life; surely we can do our part.