The Projective Land Use Model (PLUM) was designed by Goldner (1971) for the Bay Area Transportation Study Commission. The contribution of this model concerns replacing potentials by gravity models to allocate land uses. More specifically, the model allocates services and population using intervening-opportunity models. In addition, Goldner disaggregated the parameters for each of the nine counties in the Bay Area and used zone-specific activity rates and population-serving ratios to account for differences in population and employment structure.
It reflects a more general tendency to use disaggregation and a wider set of parameters in an attempt to make the models more realistic, which made them also more of a black box and a data-fitting exercise.