The Detroit Office of Campbell Ewald has been selected as brand strategy and creative partner for car-sharing company Zipcar, Inc. following a competitive review. The scope of work includes global brand strategy and campaign creative. Spending is not being disclosed. The 13-year-old company reports having more than 777,000 members and nearly 10,000 vehicles in urban areas and college campuses throughout the United States, Canada, the UK, Spain and Austria. The agency says work for Zipcar is slated to launch in spring 2013.