There are two passives which best fit this sentence: "have been told," and "were told." "are told" is grammatically possible but is, to my ear, strange. The simple present passive is usually used when describing processes, procedures, or regular routines, and the agent is not important: "Next, the beans are cleaned before they are ready to cook." or "Pictures are edited for content before being published." or "A mild sedative is administered to patients suffering from shock."
In the first, "Neither Jeremy nor his friends have been informed about the accident by the traffic police." the idea is that Jeremy and his friends do not know about the accident and cannot act on this knowledge.
In the second, "Neither Jeremy nor his friends were informed about the accident by the traffic police." the idea is that, in the past, they did not receive the information. Someone is describing the past.
One can use the simple present passive however it doesn't really fit or make sense. I think the use of "the" to modify "accident" also makes this awkward. If we change the sentence thus: "Neither Jeremy nor his friends are informed of traffic accidents by traffic officers." it makes a lot more sense, but it also changes your intended meaning (which is to describe the past or tell why Jeremy and his friends are acting a certain way.)
Perhaps another user can think of an instance in which the simple present passive in your sentence makes sense and is not contrived.