We study a representative task allocation problem called shortest paths: Let G be a graph in which the edges are owned by self interested agents. The cost of each edge is privately known to its owner. Let s and t be two distinguished nodes in G. Given a distribution on the edge costs, the goal is to design a mechanism (protocol) which acquires a cheap s − t path. We first observe that the class of generalized VCG mechanisms has desired monotonicity properties. We exploit this observation to obtain, under an independence assumption, expected payments which are significantly lower than the worst case bounds of [2, 4]. We then investigate whether these payments can be improved when there is competition among paths. Surprisingly, we give evidence to the fact that typically such competition hardly helps incentive compatible mechanisms. In particular, we show this for the celebrated VCG mechanism. We then construct a novel general protocol combining the advantages of incentive compatibl...