Martha's Vineyard High-Value Vacation Asset Audit: Island Asset Audit — +33% Secondary Residence Surcharge / Ferry-Transit Vehicle Gap / Salt Air Comprehensive Loading
Market Disclaimer: All data sourced from Massachusetts Department of Insurance rate filings for April 2026. This does not constitute legal or licensed insurance advice. CarInsuranceQuote.ai is registered at 15 Brenthall Avenue, Suite 1, North York, ON M2R 0B3.
Martha's Vineyard (Dukes County) is an island market where vehicles are transported by Steamship Authority ferry — a factor that creates unique carrier appetite issues and mid-transit liability gaps. The April 2026 MA DOI rate cycle shows +33% coastal surcharges for Dukes County,
| County | Dukes County (Martha's Vineyard), MA |
|---|---|
| April 2026 Monthly Index | $362/month |
| April 2026 Annual Index | $4,344/year |
| YoY Surge | +33% (MA DOI 2026-MA-02) |
| Save Potential | Up to $1,920/year vs. renewal |
| Island Market Factor | Ferry transit liability gap (Steamship Authority) |
| Salt-Air Depreciation Premium | +22% vs mainland MA (NADA 2026) |
| Top Carrier Q1 2026 | Chubb Island Program |
High-Value Asset Coverage Action Plan
Martha's Vineyard vehicle owners should verify their policy includes ferry-transit coverage — standard policies exclude liability during Steamship Authority transport. Chubb's Island Program and Travelers' Coastal endorsement both cover the ferry-transit window specifically.
Regulatory Timeline
| Jan 2026 | MA DOI approves Dukes County coastal island surcharge +33% (MA DOI Rate Filing 2026-MA-02) |
|---|---|
| Feb 2026 | Chubb Island Program files ferry-transit endorsement for Dukes County (MA DOI Filing) |
| Mar 2026 | NADA 2026 coastal tables: Dukes County 22% accelerated depreciation (NADA 2026 Coastal Adjustment) |
| Apr 2026 | MA DOI Q1 2026 market conduct: 3 carriers exit Dukes County market (MA DOI Market Conduct Q1 2026) |
Is car insurance more expensive on Martha's Vineyard?
Yes — significantly. Dukes County carries a +33% coastal island surcharge in the April 2026 MA DOI rate cycle. Salt-air corrosion loading, ferry-transit liability gaps, and secondary-residence non-primary-use surcharges push Martha's Vineyard premiums 38-45% above the Massachusetts state average.
Does my car insurance cover my vehicle on the Steamship Authority ferry?
Not with a standard policy. Most standard auto policies exclude liability during ferry transport. Chubb's Island Program and Travelers' Coastal endorsement both cover the ferry-transit window. Verify your policy language before shipping your vehicle.
How does salt air affect car insurance on Martha's Vineyard?
Salt-air corrosion accelerates vehicle depreciation 22% faster than mainland Massachusetts (NADA 2026). Carriers now explicitly model this in comprehensive rating — Chubb and PURE Island Programs apply a salt-air loading factor to all Dukes County comprehensive policies.
What is the best car insurance carrier for Martha's Vineyard?
Chubb's Island Program is the dominant carrier in Q1 2026, offering ferry-transit coverage, salt-air comprehensive loading, and zero-deductible glass. PURE Insurance's coastal program is competitive for vehicles with ACV above $60,000.