In transportation modeling, a model whose basic premise is that travel flows cannot be predicted with certainty and uses probability in its algorithm, as part of its output statement, or elsewhere. (TRB)


1. The relative frequency with which an event occurs or is likely to occur. 2. In statistics, the relative possibility that an event will occur, as expressed by the ratio of the number of actual occurrences to the total number…


A method of sampling in which each unit of the universe has a known chance of selection. (TRB)


Safety achieved or enhanced by compliance with administrative or operational restrictions.


A method for keeping a process within boundaries and/or the act of minimizing the variation of a process. Process control activities may include sampling, testing, inspection, and corrective action performed by a contractor in addition to QC requirements to improve…


The ratio of units of transportation output to units of output (consumer resource); for example, vehicle miles (vehicle kilometers) per operator hour, or passenger miles (passenger kilometers) per unit cost of operation. (TRB)


Meetings of the membership of a professional, technical, and or other organizations for the purpose of professional development, benchmarking or forum discussion that relate to MTA business.

Professional Services

Costs associated with General Engineering, Project Management Assistance, Construction Management Support services, Legal Counsel, Agency (Metro Staff) costs, and other Specialty Consultants


The vertical location of a guideway or a roadway as described by curves and tangents defining its position with respect to the surrounding area.


A group of related activites performed by one or more organizational units for the purpose of accomplishing a function for which the government is responsible.