We introduce a weighted gradient network on the unweighted substrate networks. The edge weight wij is defined as the power-law function of the scalar difference |hj−hi| between the two connected nodes i and j, i.e., wij∼|hj−hi|α. The jamming factor J of the whole network is defined as the average of the jamming degrees of all nodes. The jamming properties are studied for the substrate of random and scale-free networks. We find a crossover phenomenon in two networks. For α>αc (αc denotes a critical parameter, estimated to be about 1.5 for the random network and about 2.0 for the scale-free network), the value of J increases with increasing average connectivity 〈k〉 of the network, while for α<αc, the reverse occurs. In addition, the jamming effects of the two networks are compared, and we give the range of values of α and 〈k〉 that the scale-free networks have a higher level of congestion than the random networks.
