In a city where voter turnout for municipal elections has hovered around 20 percent, one group is calling for a new demographic of Somerville residents to help fill the polls: 17-year-olds.

Youth advocacy group Save Our Somerville began circulating a petition asking the Board of Aldermen to allow 17-year-olds to be able to vote in the next mayoral, aldermen and school committee races in 2011.

SOS organizer Adam Rich says the initiative took shape after realizing many of the high schoolers the group began working with a few years ago have become well-acquainted with the ins and outs of Somerville politics. In the past two years, the group has taken the city to task on fair housing issues in the midst of the Union Square rezoning project and ran a campaign asking for a city-built skate park.

“It’s a recognition of their ability to give their input on issues,” Rich said of the petition. “When we say something, our voices are heard as voters; we’re given that credence. If these kids are already really involved in what’s going on in the city, they should be given that level of credibility and decision making.”

The group has gathered 218 signatures so far. Rich said he’s hopeful the petition will gather several hundred more signatures before being presented to the Board of Aldermen. If approved, the measure will go to the State House as a home rule petition.

“We’re hoping that this is going to be a really unifying issue,” Rich said. “It’s beneficial to the community to have more voices being heard. We hope people will really get behind this when it goes to the state.”

In 2006, then Cambridge City Councilor Timothy Toomey helped bring a similar measure before Beacon Hill, but saw the measure die in committee. SOS consulted Toomey, now also a state representative, before developing their petition in hopes of garnering early support from the State House.

“It’s important for young people to get involved in the electoral process and participating,” Toomey said. “That’s a good age for them — most are seniors in high school and ready to make some big decisions in their own lives. Getting them involved early in this process will hopefully get them to vote regularly.”

Toomey said he couldn’t predict whether a home rule petition would fare better on Beacon Hill than the attempt four years ago, but that the learning experience would be valuable either way.

“If you don’t try, you’re never going to know,” he said. “Some might trivialize something like this, but it’s a good opportunity for the kid’s to make the effort.”

The petition is available at http://www.saveoursomerville.org/.