Purple parking spaces are designed to grab your attention, not guarantee you a free spot. Unlike blue accessible spaces, purple has no universal meaning. In one city it might mark a special permit program; in another, it could be reserved for a specific facility, event, or type of vehicle. Private lots can add yet another layer of rules, enforced by posted terms you agree to simply by entering.
The only reliable way to know if you can park there is to stop and check. Look for nearby signs, entrance notices, and words or symbols painted on the pavement. If you still aren’t sure, choose a clearly unrestricted space instead. A few seconds of caution can keep a convenient-looking purple space from turning into a ticket, a tow, or a very expensive lesson in local parking law.