Roadmap portal uses service desk customer accounts for customer users to login. This ensures security/safety of your customer data. On the top right corner of roadmap portal, there is a link to ‘Login’.
Clicking on that link, takes the user to service desk login page. Post successful login, user is brought back to the roadmap portal in logged in state.
You can tell the difference between a logged in & logged out user by looking at the top right corner.