JMD has led the analysis and design of numerous rail/highway grade separation projects for regional agencies such as Alameda Corridor - East (ACE), LACMTA and OCTA. JMD has been involved in regional rail/highway grade separation studies such as the Orangethorpe Corridor Study for OCTA and the original Grade Separation Study for the San Gabriel Valley Council of Governments (SGVCOG) which ultimately defined the ACE Grade Separation Program which is developing 25 grade separations in the region.
JMD has served as program manager and technical advisor to ACE and OCTA on various grade separation projects and has led the design of grade separation projects, from conception to ultimate construction, including some of the most challenging grade separations, including trenches (San Gabriel Trench and Montebello Trench), underpasses (Fullerton Road), overpasses (Rosecrans Avenue) and track flyovers (Sunset Avenue/7th Avenue).