A method and apparatus for generating an indicator of a risk level in motor vehicle and notifying vehicle systems when a risk level is above a specific threshold includes, receiving a plurality of driver distraction indicators, assigning a weighting value to each indicator, applying a scaling factor to the weighting value assigned to those indicators which are identified as being related, and summing the weighting values to produce an output value indicating a risk level. Distraction indicators can include on-board system and sensor outputs and stored data relating to driver attributes. Related indicators may comprise those distraction indicators relating to environmental conditions (eg. rain and low ambient light levels), or to vehicle performance to driver concentration level (eg. in-car phone and navigation system). The scaling step allows the weighting process to be refined based on the status of other received indicators.