(Center Identification Number: 77708) Transit mode share is used as a critical barometer at various geographic levels. Its magnitudes and temporal trends play an important role in both policy debates at areawide levels (nationwide, states, regions, counties, cities) and in performance monitoring at sub-area levels (activity centers and corridors). The census journey-to-work data have typically been used for areawide measurement of transit’s usual mode share, i.e., the share of workers who usually use transit for commuting. There has been much controversy and confusion in the literature about using census journey-to-work data for measuring transit mode share. The objectives of this report are to examine the controversy and confusion in the literature and to develop alternative measures of transit mode share. This report covers the following aspects: 1) a framework for considering transit mode share and its measurement; 2) the relationship between transit’s usual mode share and its actual mode share, i.e., the share of work trips that are made by transit as revealed by respondents to daily travel surveys; 3) the sensitivity of transit mode share to a variety of measurement concerns raised in the literature; 4) areawide measurement of transit mode share; 5) sub-area easurement of transit mode share; and 6) recommendations. Download the final report. For more information, contact Xuehao Chu at email@example.com or Steven Polzin at firstname.lastname@example.org.