In practice, numerous models are used: linear rate, non-linear rate, and kinked rate. The kinked rate model is used in the Trava protocol. As with the non-linear model, such models have the virtue of significantly shifting the incentives for borrowers and lenders beyond some usage level. In contrast to non-linear models without a kink, they also introduce a point of abrupt change in the interest rate, beyond which interest rates begin to sharply rise.