curvature, slip-roads and high flow roundabouts are associated with increased risk of car–cyclist collisions. Cycling advocates argue for modifications and alternative junction types that resolve these issues such as reducing kerb radii on street corners, eliminating slip roads and replacing large roundabouts with signalized intersections. Protected intersection Another approach which the Netherlands innovated is called in North America a protected intersection that reconfigures intersections to reduce risk to cyclists as they cross or turn. Some American cities are starting to pilot protected intersections. Bike box A bike box or an advanced stop line is a designated area at the head of a traffic lane at a signalized intersection that provides bicyclists with a safer and more visible way to get ahead of queuing traffic during the red signal phase. Roundabouts On large roundabouts of the design typically used in the UK and Ireland, cyclists have an injury accident rate that is 14-16 times that of motorists. Research indicates that excessive sightlines at uncontrolled intersections compound these effects. In the UK, a survey of over 8,000 highly experienced and mainly adult male Cyclists Touring Club members found that 28% avoided roundabouts on their regular journey if at all possible. The Dutch CROW guidelines recommend roundabouts only for intersections with motorized traffic up to 1500 per hour. In order to accommodate greater volumes of traffic, they recommend traffic light intersections or grade separation for cyclists. Examples of grade separation for cyclists include tunnels, or more spectacularly, raised "floating" roundabouts for cyclists. Traffic signals/Traffic control systems How traffic signals are designed and implemented directly impacts cyclists. For instance, poorly adjusted vehicle detector systems, used to trigger signal changes, may not correctly detect cyclists. This can leave cyclists in the position of having to "run" red lights if no motorized vehicle arrives to trigger a signal change. Some cities use urban adaptive traffic control systems (UTCs), which use linked traffic signals to manage traffic in response to changes in demand. There is an argument that using a UTC system merely to provide for increased capacity for motor traffic will simply drive growth in such traffic. However, there are more direct negative impacts. For instance, where signals are arranged to provide motor traffic with so-called green waves, this can create "red waves" for other road users such as cyclists and public transport services. Traffic managers in Copenhagen have now turned this approach on its head