Protected intersection
[1] At a protected junction, vehicles turning to the nearside are separated from crossing cyclists and pedestrians by a buffer, providing increased reaction times and visibility.
An alternative philosophy, design for vehicular cycling, encourages having bicycle lanes simply disappear, or "drop", at intersections, forcing riders to merge into traffic like a vehicle operator ahead of the intersection in order to avoid the risk of a right-hook collision, when a right turning motorist collides with a through moving cyclist.
Design policies which do not allow the cyclist to remain separated through the intersection have come under increasing scrutiny in recent years as causing difficulties for less capable riders,[2] leading to lower overall ridership and sidewalk riding,[3][4] and being less safe.
[8] After three decades, these designs proved to be largely a failure, with the number of kilometers cycled falling by 65% and the per-km rate of cyclists being killed increasing 174%.
As the nation again began to desire separated bicycle infrastructure, the protected intersection rose to prominence as an engineering solution for optimizing sightlines.
While used in much of the Netherlands, including Amsterdam, local road authorities in other parts of the country do not use the classic protected intersection with middle islands, preferring to have cyclists move during a completely separated all directions green phase.
[14] Other options for reducing bicycle accidents at intersections, depending on context, include the use of bridges and tunnels, and planning or reconfiguring the neighborhood street/path system so that major amenities and schools can be reached without needing to travel along busy roads.
In countries other than the Netherlands, where a segregated cycle lane came near to a junction, basic forms of protection may be used to accommodate cyclist safety.
[1] In terms of optimal spacing between the path and motorist lanes, it is generally practice to use 2–5 meters at signalised crossings and one car length >5 m at unsignalised intersections.
Wide strips are painted aside the cycle lane and 'shark teeth' (triangles with pointy end oriented toward the non priority vehicles) are used to reinforce who must yield.[where?]
[20] This protected intersection design features a number of common elements that optimise safety: Some countries such as the UK, do not permit partial conflicts.
[25] Specific facilities for cyclists are not needed at quieter roundabouts (<6,000 passenger car units per 24 hours), unless connecting roads have segregated cycle tracks.
[29] The Dutch not-for-profit organisation CROW publishes design manuals summarizing best standards for bicycle infrastructure in the Netherlands, where biking is a much more dominant mode of transportation than in the United States.
[30][31] The organisation's and country's longer experience with synthesizing biking and driving transportation modes have made CROW's design manual internationally popular.
This sparked controversy, especially after ambassador of Dutch bicycle infrastructure Mark Wagenbuur criticised NACTO for doing so in a prominent trade blog.
[35] In 2015, Alta Planning + Design published schematics and some realisations of "protected intersections" in the US and Canada closer to Dutch practice.
In 2021, the Invest in America Act became law, which amended the federal Highway Safety Improvement Program to recognize "protected intersection features" along with other separated bikeway treatments.
