I am happy in understanding that you can specify times when the quiz is accessible for people to make attempts, before the opening time the quiz will be unavailable to students, they will be able to view the quiz introduction but will not be able to view the questions and quizzes with start times in the future display both the open and close date for students.
As an additional preference at the attempt of the quiz, I'd like to have the option enable a timed reading period. Whilst this is occurring, the student would be unable to enter any answers. Once the reading time period is up, the new time limit applies in completing the quiz/exam.
The "reading time" is an important addition to the way we teach and specifically allows the students to raise any points with the instructor such as reclarification of a question, for example.