I have tried:
safariDriver.get("file:///Users/pathToMyHtml/index.html");
safariDriver.get("/Users/pathToMyHtml/index.html");
but none of them worked. I use Java and macOS Sierra. (If I open a page from http:// it's working)
The root cause is Selenium version. You need to upgrade Selenium to version 3++. It works fine on my machine with Selenium 3.4.
See issue at: https://github.com/seleniumhq/selenium-google-code-issue-archive/issues/3773