An approach is provided for detecting venue trips and related road traffic. The approach involves, for example, processing probe data to identify a trip related to the venue. The trip is traveled by a probe vehicle generating the probe data within a timeframe associated with an event occurring at the venue. The approach also involves generating an influence graph comprising one or more roads used by the probe vehicle during the trip. The approach further involves determining a traffic parameter for the one or more roads of the influence graph. The approach further involves computing a traffic impact score for the venue, the event, or a combination thereof based on the traffic parameter.