Yes, the new use-of-force policy at the Baltimore Police Department will likely prevent some police brutality. It seems it would be nearly impossible to prevent all brutality because the force is made up of individuals. However, the mere act of creating the policy will encourage officers to be aware of their actions and the actions of their fellow officers.
The use-of-force policy in the Baltimore Police department has not been revised since 2003, and was in sore need of review. In an increasingly forceful world, police officers need to have clear boundaries as to what is and is not acceptable. Levels of force are defined with a clear standard of reporting for each. Officers are instructed to attempt to defuse situations, and only use force proportional to the situation. In addition, the new policy allows and even requires other members of the police force to intervene is force used is not appropriate to the situation. This will create accountability, as well as boundaries - both of which will help to decrease the use of force.
It is a mindset and a pattern. To truly change, the old guard of the police department must move on or be removed to effect true change in Baltimore. Changes to words in the use of force policy doesn't change the reaction of an officer at a flash point in a confrontation, nor does it change the expectations of the citizens of the city.
No, Baltimore's new use-of-force policy will not prevent police brutality, however, it will lessen the number of instances in which police brutality occurs. Police brutality cannot be eliminated altogether because some police are likely to still keep engaging in brutality. Other police, however, will be deterred from brutality by the new policies.