Holliston has hired McMahon Transportation Engineers & Planners of Taunton to complete an analysis of traffic signals and a conceptual design for the Washington Street corridor through the center of town between Elm Street and Quincy Place. The firm was hired for $24,925, appropriated at this spring’s annual Town Meeting. The work will include a study of the need for traffic signals, computer modeling, and the design for a possible integrated traffic signal system for three downtown Washington Street intersections, at Central Street, Hollis and Charles streets, and Exchange and Green streets, according to an announcement from Town Administrator Paul D. LeBeau. Traffic “calming” measures, which could include medians, enhanced pedestrian crossings, and traffic warning devices, will also be evaluated. Final recommendations are expected to be ready for presentation to town boards by December or January. Full story for BostonGlobe.com subscribers.