For many families like mine?with members who are on the spectrum or have other sensory or mental disorders?parks and playgrounds are vitally important It?s a beautiful Sunday in July. We?ve already taken our son Finn to CVS to buy him his favorite Tic Tacs, and now we?re at Trader Joe?s. On the usual Sunday line at either store, he?ll rock from one leg to the other, bounce in place, or stim, flapping his wrists up and down. He has autism spectrum disorder, and patiently waiting isn?t a skill he?s mastered, even though he?s almost 12 years old. He?s rocking now, further agitated by the level of activity and noise. His behavior draws curious stares, but I?m used to these, and am frankly past the point of caring what others think. Nevertheless, I?m on guard, my senses at attention. I?ve had enough outings with Finn to know what?s possible. While I?m unloading the grocery cart he might suddenly bolt to the back of the store or out the front door, forcing me to abandon my spot in line in order to chase him. He might vigorously open and close his bent arms at chest level, how he communicates ?all done,? a desire which if not immediately met may prompt sudden aggression, as it did last Sunday, when he hit me in the face, knocking off my glasses and cutting the bridge of my nose. Today we?re okay. Our cashier sees his impatience, the way he keeps touching the cart ahead of ours, and when it?s our turn she lets him help scan the items and load them into the cart, activities t...