The procedure for estimating a household model of mode choice is described. The tour-based mode choice model incorporates interpersonal interactions within the household explicitly in an agent-based random utility modeling framework. Household interactions include vehicle allocation, ridesharing to joint activities, and drop-off and pickup. Because of the complex nature of the model decision structure, choice probabilities are simulated from direct generation of random utilities rather than through an analytical probability expression. The computational requirements for the simulation are large. Therefore a grid of computers is used in parallel to perform the necessary calculations and a genetic algorithm is used for parameter estimation. A brief description of the model, the full model results, and a discussion of the computational techniques used in parameter estimation are presented.