VMt

VMT stands for Virtual Method Table in computer science. It is a mechanism used by several object-oriented languages to support dynamic dispatch of virtual methods. A VMT is typically a per-class table of function pointers, one entry per virtual method. Each object carries a reference to its class’s VMT; when a virtual method is invoked, the runtime uses the object’s VMT to select the correct function implementation, enabling polymorphism. The exact layout and naming conventions vary by language and compiler—some call it a vtable, virtual method table, or dispatch table—and it is generally considered an implementation detail rather than a language feature.

In the context of transportation planning, VMT means Vehicle Miles Traveled, a metric that sums the total miles driven by all vehicles in a defined geographic area and period. VMT is used to assess travel demand, forecast traffic, estimate emissions, and evaluate infrastructure investments. It is influenced by factors such as population, land use, income, and prices. Data for VMT come from travel surveys, traffic counts, and model estimates. While useful, VMT has limitations: it does not directly capture trip purpose or origin-destination patterns, and it can obscure differences in vehicle efficiency or congestion.

Because VMT is an acronym with multiple meanings in different domains, its interpretation should be guided by context.