Some parts of the site require signing in. Users have different levels of access based on their role. There are public users, passport users, data contributors, and admins.

• Anyone can sign up for a public account.
• Public users can request passport accounts, which give them access to more data.
• Admin users can review passport requests and grant or deny the account upgrade.
• Users need to be signed in when accessing data.
• Users remain logged in between sessions, up to a limit.
• Other requirements