JOBMOD2 is a model that makes quantitative estimates of the total employment income and jobs supported by federally funded highway improvement projects. This includes not only the direct employment of construction workers, but also all those workers who are required to produce inputs to the construction project. It also goes a step further by estimating the number of jobs that are supported by the growth in consumer expenditure that arises due to all the employment income from those jobs supported by the project. Thus, it provides a very broad definition of the total employment impact of expenditures on highway improvements. The term "highway improvement" can cover a broad range of things, including construction of new highways; reconstruction of old highways; construction, reconstruction or major repair of bridges; improvement of signal systems and traffic flow systems for the purpose of congestion reduction or safety enhancement; and highway alterations for environmental purposes such as the installation of sound barriers. Furthermore, a substantial proportion of highway funds may be spent not on construction per se, but on engineering design services. Since these different types of activities will produce different employment impacts, JOBMOD2 makes it possible for the user to specify the highway improvement type. Highway construction is a relatively labor intensive activity that directly employs a variety of people including laborers, equipment operators, vehicle drivers, engineers, managers and supervisors. Thus, assuming that there is slack labor supply, each construction project creates a number of new jobs directly. It also creates a number of jobs indirectly through its incremental demand for inputs such as steel, concrete, aggregates, lighting equipment etc. Labor is required to produce all of these inputs and to produce inputs to the production of these inputs.