Accessibility of methadone treatment via public transit for syringe services program participants in Miami-Dade County, Florida.

Methadone is an opioid receptor agonist medication used in the treatment of opioid use disorder (OUD). Geographic distance to opioid treatment programs (OTPs) is a major barrier to treatment, given requirements for direct observation of dosing and periodic drug screens, and 'methadone treatment deserts' are defined as a public transit threshold of 30 minutes. The purpose of this study was to examine public transit access to methadone treatment for participants of a syringe services program (SSP) in Miami-Dade County, Florida. Public transit times were calculated using the R library r5r, which facilitates multi-modal transportation network routing. General Transit Feed Specification data was combined with street network data from OpenStreetMap for Miami-Dade County. Transit times were estimated from the population-weighted centroid of each zip code (n=79) with participants of Miami's only SSP (n=1597) to the nearest OTP (n=4) using 10 departure windows aligned with OTP service hours. The mean one-way transit time from zip codes with SSP participants in Miami-Dade County to the nearest OTP was 80 minutes. 75 of the 79 (95%) zip codes with SSP participants in Miami-Dade County have a mean transit time to the closest OTP greater than 30 minutes. Transit times differ substantially between zip codes with different numbers of SSP participants, but not between departure windows. Nearly all zip codes with SSP participants in Miami-Dade County can be classified as 'methadone treatment deserts'. Geographic isolation of methadone treatment from public transit routes represents a significant barrier to equitable OUD treatment.