I'll recommend you try the city bus. I used it both ways in October and it
worked great. Runs every 30 minutes and leaves yiu off - and picks you up -
just 1 1/2 blocks from the Westin.
There are discounts for Super Shuttle posted on website too. Here is link
to schedule. Fare is $3.75 EXACT CHANGE each way.
_Port Authority of Allegheny County > Schedules & Maps > Airport Service_