Fuel optimizers are software products that reduce the fuel cost of motor carriers at the ''point of purchase'' by optimally determining: (i) which truck stop(s) to use, and (ii) how much fuel to buy at the chosen truck stop(s). These products, however, upset many truck drivers by ''confiscating'' their freedom to choose truck stops. Consequently, users are suffering from limited actual cost savings due to low driver compliance rates. We develop a decision support system that reduces the fuel cost of motor carriers at the point of purchase without confiscating the drivers' freedom to choose truck stops, so that higher driver compliance rates are expected.