CONCORD, N.H. — As the holiday travel season gets underway, the state is seeking public comments on how to improve the rest areas and welcome centers along New Hampshire’s roadways.

The Departments of Transportation and Resources and Economic Development are kicking off a series of public hearings Tuesday, starting at the transportation headquarters in Concord. The study on the centers began in January and has included analysis of traffic and parking data, visitor counts, budget information, interviews with trucking companies and researching the best practices in other states. Officials say they want to know how services can be improved at the centers, which vary in size and service across the state.

Transportation officials say 5 million visitors stop in the centers annually.

Of the 16 centers, nine are open year round, three operate seasonally and four are closed. The state budget includes about $3 million to operate the centers.

Four more hearings will be held through early January, in Keene, Lebanon, Lancaster and Seabrook. Dates and locations are available on the departments’ websites