BOSTON – Massachusetts is embarking on a multi-year effort to put new numbers on major highway exits, a change that Highway Administrator Jonathan Gulliver says will help motorists with calculating driving distances and put Massachusetts in compliance with a federal mandate.

The changes will be undertaken from west to east, and the effort will be discussed at public meetings next month in Lenox, Northampton and Worcester.

Exits on I-90, I-93, I-95, Route 3 and I-495 will be affected.

While motorists become accustomed to the transition to new exit signs, old exit signs will be installed at each converted exit for a minimum of two years, according to MassDOT.

Installation of mile-based exit signs will begin in late summer 2020 and officials hope to complete the effort by the spring of 2021.

The switch is mandated under the Federal Highway Administration’s 2009 Manual on Uniform Traffic Control Devices.

The federal government will cover 90 percent of the project’s estimated $2.8 million cost.

Public meetings are planned Monday, Dec. 9 in Northampton; Wednesday, Dec. 11 in Lenox and Monday, Dec. 16 in Worcester.

Additional public meetings are planned in 2020, but have not yet been scheduled.