Excluding heavy truck traffic on the residential roads North and Myrtle Streets may seem like a good idea at first, but if this rule is enacted, what will it mean for neighboring streets, like Temple, Laurel and Union, which might have to absorb this type of traffic?

The Board of Selectmen pondered this question this week after learning that Pembroke town officials would like to exclude heavy truck traffic on Pleasant Street and Spring Street in Pembroke and on Old Ocean Street in Marshfield. To accomplish this, they need Duxbury’s permission to include North and Myrtle Streets, since they connect to the roads in these neighboring towns. Jed Cornock, a transportation planner at the Old Colony Planning Council, explained that Pembroke has asked the Council to perform traffic counts on roads that connect Route 139 to Route 53. He found that truck traffic was higher than usual on these back roads.

“Those roadways satisfy a general threshold of at least five percent of heavy vehicles over a 48 hour period,” said Cornock. “That threshold is set by Mass. Department of Transportation.”

Mass. DOT is the permitting agency for heavy vehicle exclusions, said Cornock, adding that the DOT also looks at the conditions of the pavement and how the land is used along the roadways in question.

“It’s purely residential in that area,” said Cornock. “That five percent (of truck traffic) is unusual.”

Heavy vehicles are defined as weighing 5,000 lbs and having two axles or six or more tires. Cornock said heavy vehicles with business on excluded roads may still proceed; these include oil delivery trucks, UPS vans and landscape companies.

To attain a heavy vehicle exclusion zone, all three towns must sign on to the idea.

DOT will also look at how the exclusion will affect alternate routes, which Cornock said will include “basically all of the surrounding routes.”

Some of the neighboring roads already have truck exclusions on them including Brick Kiln Lane, Water Street and Oak Street in Pembroke, Acorn Street in Marshfield and Lincoln Street in Duxbury. All of these streets run north to south and have been used by trucks to get to major roads, like Route 139 or Route 53, said Cornock.

“If you’re excluding truck traffic from this route and enforcing it, you’ll have potential impacts on basically all of the surrounding routes which trucks may use to get from 139 to 53,” Cornock said.

Many roads in Duxbury could be impacted, including Keene, Union, Temple, Laurel and Franklin Streets.

Selectman Shawn Dahlen pointed out that if the truck exclusions were enacted on North and Myrtle Streets a truck leaving Route 53 in Duxbury and traveling up Keene or Union Street would run into the exclusion zone and would be forced to turn around as there are no other connecting roadways.

Selectmen did not take action on Pembroke’s request at their meeting. Instead, Town Manager Richard MacDonald said he plans to call a public hearing on this issue to involve the affected residents. The Duxbury Highway Safety Committee is meeting this week on this topic and will issue a recommendation to selectmen.