The Massachusetts Bay Transportation Authority (MBTA) overhauled its advertising policy and clearly defined its guidelines as a way of deterring lawsuits, which have cost the system hundreds of thousands of dollars to battle. Ads involving abortion rights, the AIDS Action Committee and ads decrying cruel animal traps are examples of advertising that have been denied placement by the system. Advertisers protesting this action have involved the MBTA in several lawsuits over the years. The system is currently embroiled in a 11/2-year-old federal lawsuit with Change the Climate, a Greenfield-based group, over pro-marijuana ads. The MBTA has spent about $560,000 so far fighting this suit, which is still in litigation. Previously, the MBTA did not have a written advertising policy in place. Ads were reviewed by the marketing and communications department, legal representatives and representatives of the general managers’ office, basing their decisions on whether the ads were deemed obscene, violent or harmful to children, and if they denigrated groups based on gender, race or political affiliation, said Lydia M. Rivera, MBTA spokeswoman. “There really isn’t anything new to this policy. We’ve just tightened it to clear up some loose ends that might be misinterpreted, and strengthened it,” Rivera said. The new policy includes guidelines, which still require approval from the MBTA’s board, that state the transit agency will not display or maintain any advertisements that are demeaning or disparaging, promote the use or sale of tobacco, contain an image or depiction of a firearm, contain profanity or promote adult-oriented goods or services. MBTA General Manager Michael H. Mulhern will now be a part of the review process, determining if the ads fall into the set categories. “We are confident that [the policy] will curtail the number of suits and give people a clear definition of what the guidelines are without any question,” Rivera said. Although some ads that may have been rejected in the past will be reconsidered, such as a recently banned church ad, Rivera states that the pro-marijuana ads will still not be allowed placement. “The policy is conservative in a good way,” Rivera said. “Boston, overall, is a conservative town.”