Voluntary programs have been used with varying degrees of success to address a variety of environmental issues. The goal of the present study was to assess mariner response to a voluntary program to reduce the threat of vessel collisions with the endangered North Atlantic right whale Eubalaena glacialis. The program involves the creation of temporary zones, dynamic management areas (DMAs), in which vessel operators are requested, but not required, to either navigate around the area or travel through at speeds of 10 knots or less. Using remotely sensed automatic identification system data, we analyzed 3324 transits made by 1100 individual vessels, the majority of which belong to the international commercial shipping industry utilizing east coast ports of the USA. In general, we observed very little change in vessel operations in response to the DMAs. The mean transit speeds for cargo, tanker, and passenger vessels within the DMAs exceeded the requested maximum of 10 knots and differed little from speeds used outside DMAs. In addition, few transits appeared to involve efforts to navigate around the DMAs. Therefore, we conclude that the program likely had only a modest consequence in reducing vessel collisions with whales, at least as measured by vessel operations. These results may have application to other settings where voluntary programs are contemplated or implemented.