From a fact sheet of the Surface Transportation Policy Partnership:
Transportation policy has a strong, positive relationship with job creation and access. The transportation system should support job creation and grant all people access to good jobs. Unlike past transportation decisions that have focused on short-term solutions and have ignored large sections of the population, modern transportation investments must expand opportunities and improve quality of life. . . .
In recent years, proponents of increased investment in new highway capacity have used job-creation as a rallying cry for their cause, saying that money spent on these new roads will lead to a surge in new jobs. While transportation investment should not be seen as primarily a jobs program, economic studies indicate that transit capital investments and operations funding are even better sources of long-term job creation.
According to a recent study by Cambridge Systematics, 314 jobs and a $30 million gain in sales for businesses are created for each $10 million invested in transit capital funding, and over 570 jobs are created for each $10 million in the short run. While new highway construction does lead to an increase in employment, these jobs are mostly for non-local workers: road engineers and other specialists who come in to an area for a specific job and then leave when it has been completed. On the other hand, transit investments create a wealth of employment opportunities in the short and the long run. Transit system construction leads to an impressive level of short-term job creation, and once the systems are finished, a long-term source of high-quality jobs. Of the 350,000 people directly employed by public transportation systems, more than 50 percent are operators or conductors. In addition, 10,000 to 20,000 professionals work under contract to public transportation systems or are employed by companies and government offices that support these systems. Thousands of others are employed in related services (i.e. engineering, manufacturing, construction, retail, etc.). . . .