Washington State Ferries officials said Friday the ferry system’s customer service lines have been overwhelmed with calls from people trying to make reservations on the Keystone-Port Townsend route.

Callers have “experienced unusually long waits” during the past week, and officials said the department has received an unprecedented number of calls since the Hood Canal Bridge closed on May 1.

“We are very concerned that the volume of calls we are receiving to our customer service lines is frustrating our customers, despite our best efforts,” said David Moseley, Assistant Secretary for Washington State Ferries.

Officials said vehicle reservations on many sailings are filling up far in advance. Some people have tried to make reservations online, but have found no reservations available for the time they want to use the Keystone-Port Townsend route.

Ferry officials are encouraging travelers to visit www.wsdot.wa.gov/ferries to make reservations online.