Function
User Need
While the specific permutations vary from machine to machine, the parking garage payment terminal retains the same set of basic features: you get a ticket when you come in, you provide that ticket when you want to leave, and you pay the requisite amount to lift the gate up and exit the garage. This introduction of some basic technology to parking is undoubtably a more elegant solution than the old-school method of having a teller. The machine nominally should be faster since it can calculate and make change automatically, cheaper since you don't have to pay a teller to sit at the garage exit, and more robust since parkers can exit the garage at odd hours when a teller wouldn't be on duty. The machine is able to accept cash, credit cards, monthly passes, validated tickets, and scanned bar codes with far less error and frustration than a human. Or at least it should.The User Profile
Since the parking machine is a public piece of technology, it has to be robust to all the different users which must interact with it throughout its life-cycle. This can prove to be a challenge when you have, for example, many tourists interacting with the technology. The parking garage at Le Meridien has to be comprehended by all the different guests at the hotel, and at somewhere like MIT where the visitors are often international, this can be a tricky task. A robust user interface must be able to be support:- Both domestic and foreign users, often who do not speak English as a first-language (or at all)
- Users of a wide variety of ages, with different levels of technology familiarity
- Physically handicapped users who may have difficulty reading, reaching, hearing, or otherwise interacting with the machine
In addition to being robust to different users, the machine also needs to be able to accomodate different use cases The below study from the city planning division in Tampa, Florida (my hometown), shows that no one use scenario dominates the parking garages. A parker who is leaving a sports game for instance, which around 25% of people say they had done in the past, is likely to have to pay by cash or credit card, will unlikely know exactly how long they will be parked, and will want to complete the payment transaction as fast as possible due to the large number of people all trying to exit at the same time. A person using the garage for dining, on the other hand (40% of users), would be more concerned having their parking validated in some fashion, whereas a person parking for work (45%) would likely have some sort of monthly pass.
Tampa parker use scenarios (Source [1])
The Current Functions
Fortunately, the typical parking machine isn't too complicated a system and only has a few sub-functions. These include- The ticket printer
- The "insert-ticket-here" slot
- The feedback screen
- The payment terminals
- (Optional) The monthly pass/hotel card reader
- The receipt receptacle
A Simplified Process
The parking industry has decided that tickets are absolutely necessary, but they aren't absolutely integral to the parking transaction. The true desired user experience is one which is simple to understand and removes any extraneous steps which could contribute to driver confusion. The core features of parking are simply: