Advisory bike lanes are bicycle infastructure that allows for dedicated bike lanes in both direction of travel while having one single vehicle travel lane. Advisory bike lanes are clearly marked by red asphalt to draw drivers attention to them. The dashed lines of the bike lanes means that cars are able to use the bike lane if no bikes are present to pass another car. If there are two biycles and one vehicle then the facility functions normally. In the case of two vehicles and one bicycle, one of the vehicles must enter the un-occupied bike lane to safely accomodate all vehicles. The conflict with advisory bike lanes arises when there are 2 vehicles and 2 bicycles on the street at the same time. In this situation one of the vehicles would have to pull aside to allow the oncoming vehicle to pass through. 

Advisory bike lanes allow full bicycle facilities in narrow roads that usually in the United States have two vehicle travel lanes and no bicycle facilities. These facilities prioritize bicycles over vehicles by create designated facilities for them.