An alternative expression for the temperature dependence of hopping conductivity is proposed. A conduction model is proposed based on a collection of many independent Arrhenius-type processes. The density in the material considered has a A-shaped distribution as a function of activation energy, for example Gaussian, isosceles, and scalene distributions. The validity of the model has been checked with the electrical-conductivity data of disordered carbon fibers which show a metal-insulator transition. The result is that the conductivity data between 4 and 250 K fit well to the form T 2 [1-exp(-E/kT)] 2 , where T is temperature and E activation energy, and is related to the degree of disorder in the system