On the basis of the octane-number topological equivalents (TEs) constructed earlier by the inverse function method, related to the octane numbers by a biunique function, and linearly dependent on the number of carbon atoms n for n-alkanes, the octane numbers of alkenes have been simulated with the use of optimal topological indices. The models obtained suggest the maximum attainable (within linear QSPR approaches) accuracy of calculation, which exceeds by a few orders of magnitude that of previously known procedures. The octane numbers are predicted for 68 alkenes that have not been characterized experimentally.