What is Reverse Onus?

Legal Definition
A reverse onus clause is a provision within a statute that shifts the burden of proof onto the individual specified to disprove an element of the information. Typically, this provision concerns a shift in burden onto a defendant in either a criminal offence or tort claim. For example, the automotive legislation in many countries provides that any driver who hits a pedestrian has the burden of establishing that they were not negligent.
-- Wikipedia