In addition to the environmental and right-of-way acquisition risks, there are several other risks that are commonly (though not necessarily) allocated to the public sector in concession agreements. One good example is the risk of changes in applicable law that could have a deleterious effect on the private partner's revenues or costs. The private partner usually has no control over or way to mitigate such a change in law risk, and therefore it is usually allocated to the public sponsor. The public sector also typically assumes the risk of providing policy and emergency services on a public-private facility, although the private operator may contribute to such costs above a threshold amount.