Bike lanes (US) or cycle lanes (UK) are types of bikeways (cycleways) with lanes on the roadway for cyclists only. In the United Kingdom, an on-road cycle-lane can be firmly restricted to cycles (marked with a solid white line, entry by motor vehicles is prohibited) or advisory (marked with a broken white line, entry by motor vehicles is permitted). In the United States, a designated bicycle lane (1988 MUTCD) or class II bikeway (Caltrans) is always marked by a solid white stripe on the pavement and is for 'preferential use' by bicyclists. There is also a class III bicycle route, which has roadside signs suggesting a route for cyclists, and urging sharing the road. A class IV separated bike way (Caltrans) is a bike lane that is physically separate from motor traffic and restricted to bicyclists only. Effects According to a 2019 study, cities with separated bike lanes had 44% fewer road fatalities and 50% fewer serious injuries from crashes. The relationship was particularly strong in cities where bike lanes were separated from car lanes with physical barriers. Research published in 2020 showed insights from communities where on-road cycling for transportation is less common, particularly in the Southeast U.S. and reported that potential bikers say separated bike lanes would make them more likely to participate in active transportation. However, scientific research indicates that different groups of cyclists show varying preferences of which aspects of cycling infrastructure are most relevant when choosing a specific cycling route over another; thus, in order to maximize utilization, these different groups of cyclists have to be taken into account. A 2021 review of existing research found that closing car lanes and replacing them with bike lanes or pedestrian lanes had positive or non-significant economic effects on nearby businesses. United States According to the National Association of City Transportation Officials (NACTO) bike lanes are an exclusive space for cyclists by using pavement markings and signage. Bike lanes flow in the same direction as motor vehicle traffic and is located adjacent to vehicle movement. Conventional bike lanes provide limited buffer space between vehicles cyclists, as those with protective space are referred to as buffered-bike lanes. Buffered bike lanes are similar to conventional lanes but provide a buffered space between vehicles and cyclists hence the name. The extra space can be between moving vehicles and/or parked vehicles and is typically 3-feet wide, the width of a car door.