From safari error console:

    car_data.js.gz:1 SyntaxError: Parse error
    ReferenceError: Can't find variable: car_data

I don't have access to OSX, it works on my Safari under Win7.

This is what I got when I tried in Safari 5.05 under Snow Leopard. Not sure if it helps since you can't test but here ya go. Also shows the errors I got in the error log console.

http://img4.imageshack.us/img4/3154/screenshot20110815at134....

I think it didn't like the gzipped JS file with the data. Not sure why, pretty much all modern browsers should support it.

Try naming the gzip file something else, like .js.jgz. Safari automatically opens many archive types, including, I believe, gzip.

It worked fine in Safari Version 5.1 (7534.48.3)