A collision avoidance system for use in a vehicle. The system facilitates the avoidance of other vehicles and other potential hazards or obstacles. A sensor subsystem is used to capture sensor data relating to one or more areas outside the vehicle. Sensor data is sent from the sensor subsystem to a threat assessment subsystem for generating a threat assessment from the sensor data. The threat assessment is then sent to a feedback subsystem so that if appropriate, a response is generated by the system. The response can take the form of a visual, audio, and/or haptic warning. The response can also take the form of changes with respect to the vehicle itself, such as an automatic reduction in speed. The system can incorporate user-based attributes, vehicle-based attributes, and environment-based attributes in evaluating potential threats and contemplating system responses to those threats. A wide variety of different heuristics can be applied by the system. The system can be configured to minimize nuisance alarms and accommodate distinctions between users based on user preferences, user history, and other factors.