This paper reports on the use of a genetic algorithm based technique,
GABBA, to solve bi-level linear programming (BLLP) problems. GABBA is
used to generate the leader's decision vector, and the follower's reac
tion is obtained from the solution of a linear program. GABBA is diffe
rent from the usual genetic algorithms because we only use mutations,
alleles of base-10 numbers, and a survival strategy that is suited to
BLLP. Results show that, while it takes more cpu time, GABBA gets clos
er to the global optimum than Bard's [1983] grid search technique for
problems of most sizes.