Can I just send my ACT scores to colleges?

I took both the SAT and the ACT. Here were my scores:

SAT: 2000 (CR:680, Math:660, Writing:660)
ACT: 34 (English:35, Math:33, Reading:35, Science:31, Writing/English:32)

Since my ACT score was much better than my SAT score, then can I just send my ACT results instead of my ACT and SAT results unless my colleges require it?

My main concern as far as test scores go are with my reach schools: UPenn (which requires both SAT and ACT results), Cornell, Princeton, Swarthmore, and Johns Hopkins.

Send both only if required by the colleges. They will use the higher score.