Depends on a lot of things. Is it a private school? Is it a public school? What did they find? Did you sign any paperwork before parking your car in the lot? Was a drug dog walking around that gave police/school administrators probable cause to search your locker and car? How did they know to search your car and locker?
There is no simple "yes" or "no" answer to this question.
Licensed in MD, PA and DC. This is not legal advice. I am not your attorney until we have mutually agreed that I am your attorney. You should consult with an attorney licensed to practice in your jurisdiction regarding your specific circumstances.
Schools have a lot of latitude in these areas, but not absolute, of course. The challenge is that much of what can justify an act of detection or enforcement by school authorities is beyond your knowledge or ability to determine (such as an anonymous or confidential statement by an informant). In general, if the school has an articulable reason to take an action, the may be legal. But the legalities don't ordinarily get sorted out until there is some sort of enforcement proceeding at issue.
School-provided lockers are totally vulnerable to search, even if the school will admit to the practice. Cars parked at the school are particularly vulnerable because there is no necessity for you to use the school's premises to park. Your ability to get the education provided by the school is not dependent on the opportunity to park your car on school premises. So the school can limit the right to park on school property to those who agree (implicitly or explicitly) to enhanced detection and inspection procedures.
Total prudence: don't park at school and don't take to school anything you don't want searched (backpacks, electronic devices such as tablets, phones, etc.). What isn't on school premises is not likely to be subject to search. What is there to be searched, should be presumed vulnerable to search even if it is subsequently determined that it shouldn't have been. And even an unlawful search will not protect a student from all bad consequences such as expulsion and other school discipline. And police and prosecutors are not always estopped from prosecuting crimes by the unlawful searches of school administrators.
Best practice: keep private and personal stuff completely away from school property.
My responses to questions on Avvo are never intended as legal advice and must not be relied upon as legal advice. I give legal advice only in the course of an attorney-client relationship. Exchange of information through Avvo's Questions forum does not establish an attorney-client relationship with me. That relationship is established only by individual consultation and execution of a written agreement for legal services.
As has been noted, the answer is "that depends." While private schools cannot take away your 4th amendment rights, you would probably be required to waive those rights as a precondition of attending the school. The contract would require you to accept the Student Handbook, which would say that there is no "reasonable expectation of privacy" on school grounds.
If you are speaking of a public school, then the answer is no the school policies cannot supersede your rights. You are required to go to school so they cannot force you to give up your rights. That said, the 4th amendment rights speak to what the law enforcement authorities cannot do. In most istances the school administration are the ones who are searching lockers and cars, etc. I have seen cases where the police office was right there, but it was an administrator doing the search. School administrators are not held to the same standards as a police officer would be held to. Again, many schools make it clear that the use of a school locker, or the parking of a car in the school parking lot means thta you are consenting to a search.
Its a bummer, but that is the way it is.