The initial review of a pilot project by the Vancouver, Washington Fire Department suggests responding with SUVs rather than engines to low priority calls will keep engines available for priority calls and cost less money. The department spends $1.34 a mile to drive an SUV. It costs $7.47 a mile for an engine.

 http://www.columbian.com/news/2013/jun/30/fire-department-suvs-road-tested/