We faced unique security challenges in conducting a field study in freestanding mobile research facilities. This challenge required a continuing dialogue with the Baltimore Police Department (BPD), district commanders, and community affairs police officers. The BPD was receptive and supportive of the goals of the study. They provided important guidance for selecting vehicle deployment sites and included our sites in their routine patrols. The study maintained a liaison with BPD's community affairs division without arousing suspicion from the community. Providing safety for participants and staff also required that we train our staff members on personal and property safety. The MRVs had 24-hr security surveillance by the HANDLS security staff. The use of an automated debit card payment method was adopted for compensation, eliminating the need for on-site cash.
