Ridership Estimation for an Existing Transit Corridor with New Bus Rapid Transit Service

Ridership estimation is a critical step in the planning of a new transit route, or change in service. Very often, when a new transit route is introduced, the existing routes will be detoured, vehicle capacities changed or service headways adjusted. This has made ridership forecasts for the new, existing and modified routes challenging. This paper proposes a model that forecasts the ridership of all routes along a corridor when a new Bus Rapid Transit (BRT) service is introduced, and existing regular bus services are adjusted. The model uses demographic data along the corridor, a recent origin-destination survey data and new and existing transit service features as inputs. It consists of two stages of transit assignment. In the first stage, a transit assignment procedure is performed with the existing transit demand on the proposed BRT and existing bus routes, so that adjustments to the existing services can be identified. This procedure is performed iteratively until there is no adjustment in services. In the second stage, the transit assignment procedure is carried out with the new BRT and adjusted services, but incorporates a potential growth in ridership due to the new BRT service. The outputs of the model are ridership for all routes and route segments, boarding and alighting volumes at all stops and a stop-by-stop trip matrix. The proposed model is applicable to new BRT routes with dedicated lanes or shared lanes. The application of the proposed model is demonstrated via a case study along the Alameda Corridor in El Paso, Texas.