Hot summer days have stretched on endlessly this year, warming an ocean that just six weeks ago was chilly enough to take the breath away.

On the north shore the water is pleasantly cool, inviting long evening swims at flood tide that stretch the limbs and clear the head. On the south shore where waves crash against sand, children and tiny shorebirds dash in and out of the foamy surf in comfortable harmony with one another. It’s been said that saltwater is the cure for just about everything — and few could disagree with the prescription.

Beaches are crowded with tourists and their colorful accoutrement: umbrellas, towels, coolers and kayaks.

Offshore, graceful sailboats round marks set out for summer regattas, their kite-shaped sails dotting a wide blue horizon.

Island harbors are jammed with recreational boats of every description, from opulent yachts to rowing dinghys, often moored alongside the sturdy rigs kept by working watermen who still earn their living from the sea.

Since the end of the whaling era, Martha’s Vineyard has been a mixed-use place: a summer resort for vacationers and seasonal homeowners, a year-round community for working people, families and children. In the sixties and early seventies, when real estate prices were low and open space was abundant, the two groups seemed to mingle easily. It was hard to tell the professors from the fishermen, the writers from the farmers.

The Vineyard continues to enchant, but the laid-back vibe that once marked the Island in the lazy days of summer has been changing for some time. Fifty years ago last month sleepy, unknown Martha’s Vineyard suddenly vaulted into the national spotlight with the tragedy at Chappaquiddick. The filming of Jaws, the visits of two sitting presidents, first Bill Clinton, then Barack Obama, brought new attention to the Island, and its fame and desirability spread.

Today, traffic snarls key intersections in the summer months. Once-pristine ponds are tainted with effluent. Exploding real estate prices have fueled a year-round housing crisis no one has yet figured out how to solve. A new caste of visitors with greater demands and different expectations for their vacation are redefining Vineyard culture.

Adam Turner, executive director of the Martha’s Vineyard Commission, speaking this week about traffic issues, summed up a broader question that has echoed in backyards, over dinner, under tents and in meeting rooms this summer. What do we want the Vineyard to become?

“The Island is nearing a moment where it’s going to have to decide whether it’s going to maintain its rural character or it’s going to begin to shift to a more suburban one like the Cape,” he said.

Or maybe that moment is already here.

Grappling with identity is not a new struggle for the Vineyard. The Martha’s Vineyard Commission was created in 1974 to ensure that the Island’s unique assets were protected. Nine years later, the land bank was formed to prevent too much open space from being gobbled up by development. And in a nonbinding referendum in 1997, voters in all the Island towns called for limiting ferry traffic to 1995 levels.

But our collective sense of urgency to protect what sets the Vineyard apart seems to have has ebbed. The problems have crept up on us and now seem too large, too complex, too numerous.

This week, the Gazette is launching a community survey on one aspect of this issue: the effect of motor vehicles on Martha’s Vineyard. The goal is to understand the role of traffic on our enjoyment of the Island and to generate ideas about how to address that. It is within our power, as Islanders, to say how much is too much.

As the calendar turns to August, suddenly summer is halfway gone. This is peak season, with incoming ferries loaded to the gunwales, heat, dust, blue ocean, flaming red sunsets, warm sand that invites bare feet, the Agricultural Fair, Illumination Night, fireworks exploding over Ocean Park.

The things we love about the Vineyard are still there, but now we ask, for how long?