Route 146 is a high-speed road, mostly freeway, linking RI 146 (the North Smithfield Expressway towards Providence, Rhode Island) to I-290 in Worcester, Massachusetts. South of the interchange with Route 122A, Route 146 is known as the Worcester-Providence Turnpike. Unlike most roads designated as turnpikes, the road has never had tolls, and was built on a brand new alignment in the 1930s. Similar never-tolled turnpikes are the Berlin Turnpike in Connecticut and the Boston-Providence Turnpike in Massachusetts.

A relocation project is currently underway from the recently-built Exit 10A on the Massachusetts Turnpike north into downtown Worcester. A new freeway is being built between the current two-lane road and the Providence and Worcester Railroad.