A new hybrid Hartree-Fock-density functional (HF-DF) model called the modified Perdew-Wang 1-parameter model for kinetics (MPW1K) is optimized against a database of 20 forward barrier heights, 20 reverse barrier heights, and 20 energies of reaction. The results are compared to other hybrid HF-DF methods with the 6-31+G(d,p) basis. The new method reduces the mean unsigned error in reaction barrier heights by a factor of 2.4 over MPW1PW91 and by a factor of 3 over B3LYP.