If you’re used to referring to a particular interstate highway exit, like Exit 5 on Interstate 95, when giving directions to your house or some other destination in the Attleboro area, better think again.
Exit 5 could become Exit 6, according to a list of proposed exit numbers under review by the Massachusetts Department of Transportation. And, almost every other exit number on I-95 or interstates 495, 295 or 195 in the Attleboro area could change, as well.
MassDOT is in the process of working out new numbers as part of a federally mandated conversion to a system based on mileage, rather than the current sequential numbering of exits.
Mileage-based numbering already is the rule of the road in 45 other states, including Maine.
The new exit numbers have not been finalized, and no specific timeline has been set for rolling out the new system.
However Hingham archivist and authority on Massachusetts highways Robert Malme recently published a list of old and new exit numbers he said are based on information posted on a project bid page by MassDOT.
According to Malme’s information, new numbers would be assigned on I-95 based on the distance from the Rhode Island state line. Some exit numbers would change only a little, while others would change a lot.
For example, the Route 1 South/Pawtucket interchange near the Rhode Island line would be numbered either Exit 0 or Exit 1, and the Route 123 interchange would change from Exit 3 to Exit 4.
However, the I-495 South exit would change from Exit 6A to Exit 11A and the I-495 North exit would change from Exit 7B to Exit 12B.
The changes would be even more noticeable along I-495, where the Route 140/Norton exit would change from Exit 10 to Exit 30, while Route 140/Mansfield would switch from Exit 12 to Exit 31.
MassDOT did not return an email seeking comment on Malme’s information.
According to the information posted by Malme, the state does not plan to install new exit signs but will attach new “tabs” to the signs with the new numbers. Each exit would also have signs indicating the former exit number, which would remain posted for two years.
Local business leaders are unsure how the new exit designations might affect travelers.
Jack Lank, president of the United Regional Chamber of Commerce, said the changeover could lead to some confusion, especially if it takes time for electronic mapping sites or GPS used by motorists to incorporate the new exit numbers.
Ralph Arguin of Rehoboth’s Country Gardens, a popular wedding reception and party venue, is used to giving directions to people arriving from out of state.
He said businesses like his will have to keep up with the changes to make sure guests get up-to-date information.
“It’s just something else we’ll have to do,” Arguin said. “Some people might say, ‘Just let them figure it out.’ We just want to make sure our guests are happy.”