Abstract: A method and apparatus for monitoring traffic based on traffic images includes a server that receives traffic image data from applications running on mobile devices. The traffic image data includes location data together with image data corresponding to images of traffic on passageways traveled by the mobile devices as captured by cameras associated with the mobile devices. The server stores the traffic image data in a data store and makes the traffic images available to other computing devices (e.g., mobile devices) in response to receipt of requests that indicate locations for which the images are desired. The server may also be programmed to perform image recognition processes on the traffic images to recognize the presence and proximities of vehicles in the traffic images, and based thereon, determine traffic congestion at the locations where the traffic images were produced. The traffic congestion data may also be shared with other mobile devices.