The cost of our highways

My alphabet soup of New York subway commuting (F to A or Q) has been replaced by a barrage of numbers: 23 to 14 to 96 to 75. On the subway, an occasional mysterious line closure reminded you of casualties on the tracks, but these tended to be human and voluntary. The numbered highways wear their casualties like trophies, and they are four-footed and without choice. On one morning I pass three raccoons, a deer, a coyote, several squirrels, and a mouse. I owe them each a tribute, I think, as they lie there, bloody and exposed. How can we ever repay the debt we owe the animal kingdom?