Light Rail Transit (LRT) Planned Service Disruptions (PSDs) improve service reliability, extend infrastructure’s life, and reduce the frequency and impact of unplanned service disruption caused by system failure. However, the literature on the impact of LRT PSDs on transit customers’ travel mode choice behaviour is scarce relative to that on unplanned service disruptions. This thesis’s objective is two-fold. The first part investigates transit customers’ mode choice behaviour in response to short-term LRT PSD in the City of Calgary, AB, Canada, and the second part develops a methodology to design a bus bridging service strategy for LRT planned service disruptions. A Stated Preference (SP) survey was designed to gather respondents’ mode choices under a set of hypothetical scenarios. A mixed multinomial logit model was estimated using stated preference data. Findings of this study include: 1) Stated LRT ridership dropped by about 35% during the examined LRT short-term service disruption. 2) Transit customers who use LRT payment passes (monthly, subsidized seniors, low income, and students) and are frequent weekend LRT users are more likely to stay with LRT mode in case of short-term PSD. 3) The value of time for transit users during short-term LRT PSD was found to be 11.76 /hrand13.0/hr for travel time (excluding wait time) and wait time during travel, respectively. A sensitivity analysis was conducted on critical variables to predict choice probabilities of transit alternatives, and recommendations were made to improve Calgary Transit customers’ experience during short-term LRT PSDs. This study also suggests a methodology for transit planners to provide an optimized bus bridging service strategy along a disrupted LRT section during a short-term PSD to provide a higher level of service to Transit users. An optimal bus bridging service plan (i.e., routing strategy and frequency) is suggested along a disrupted section of the LRT section, using existing infrastructure consisting of bus stops and roadways. Various bus bridging service strategies are considered in this study, with optimal bus bridging service plans based on agency and passengers’ costs for each strategy. The MNL logit model was introduced in the passenger assignment to model realistic passengers’ perceived choice behaviour to choose among the available routes. Values of time for parameters such as waiting time, walking time, and riding time, which were estimated for the city where the case study was conducted, were used. The proposed model was tested with variations in passenger demand levels and passenger distribution along a disrupted section and found to be robust against various levels of passenger demand and variations in ridership patterns. Results of the case study conducted in Calgary, AB, Canada, suggested that the proposed bus bridging service design model outperformed the conventional local route strategy and reduced passenger cost by up to 25%. The study contributes valuable insights and practical recommendations for enhancing transit services during short-term LRT disruptions.