Currently, course scheduling is the purview of individual departments. This lets departments account for the needs of their faculty and often ensures that courses within the same department do not conflict. Unfortunately, coordination among departments is not adequate. For example, MAT 330: Fourier Series and PDE and PHY 208: Principles of Quantum Mechanics, two popular courses for sophomores, are both scheduled to meet Tuesdays and Thursdays next semester from 11 a.m. to 12:20 p.m. CHM 304: Organic Chemistry, HIS 394: The Rise of Modern Biomedicine and MOL 328/WWS 399: U.S. Medical Research and Researchers, all popular pre-med courses, are scheduled for the same time slot from 11 to 12:20 on Mondays and Wednesdays. With conflicts like these occurring year after year, the current system of course scheduling clearly needs an overhaul.
Just as the Office of the Registrar has control over the final exam schedule, the Registrar should have control over scheduling classes. Final exams are scheduled to minimize the number of students with conflicting exams, and this same approach could be applied to course times. The Registrar has tomes of data going back many years on what courses individual students have taken. This data should be analyzed to identify groups of courses often taken together by individual students. The Registrar should minimize less-than-inevitable conflicts between these classes.
It is true that departments sometimes need the freedom to schedule their own classes. Many faculty members, for example, commute from New York and would have difficulty teaching a morning class. These sorts of conflicts should be dealt with on a case-by-case basis, and this is best left up to the individual departments. But the Registrar could present departments with a course schedule that is optimal for students and then ask departments to propose changes in the times for a few courses to accommodate special needs of faculty.
This system may lead to more courses being offered earlier in the morning or later in the afternoon, but such a tradeoff is acceptable if it results in fewer conflicting courses. After all, Princeton is first and foremost an academic institution, and it should optimize for the greatest number of students being able to take the courses they want.