This paper presents a monocular vision based 3D bicycle tracking framework for intelligent vehicles based on a detection method exploiting a deformable part model and a tracking method using an Interacting Multiple Model (IMM) algorithm. Bicycle tracking is important because bicycles share the road with vehicles and can move at comparable speeds in urban environments. From a computer vision standpoint, bicycle detection is challenging as bicycle's appearance can change dramatically between viewpoints and a person riding on the bicycle is a non-rigid object. To this end, we present a tracking-by-detection method to detect and track bicycles that takes into account these difficult issues. First, a mixture model of multiple viewpoints is defined and trained via a Latent Support Vector Machine (LSVM) to detect bicycles under a variety of circumstances. Each model uses a part-based representation. This robust bicycle detector provides a series of measurements (i.e., bounding boxes) in the context of the Kalman filter. Second, to exploit the unique characteristics of bicycle tracking, two motion models based on bicycle's kinematics are fused using an IMM algorithm. For each motion model, an extended Kalman filter (EKF) is used to estimate the position and velocity of a bicycle in the vehicle coordinates. Finally, a single bicycle tracking method using an IMM algorithm is extended to that of multiple bicycle tracking by incorporating a Rao-Blackwellized Particle Filter which runs a particle filter for a data association and an IMM filter for each bicycle tracking. We demonstrate the effectiveness of this approach through a series of experiments run on a new bicycle dataset captured from a vehicle-mounted camera.