Nick Falbo came up with a very interesting idea last year for improving intersection traffic flow for bicyclists he called the Protected Intersection. The
bicyclists cross each leg of the intersection parallel to pedestrians and wait in corner refuge areas that are protected by islands instead of riding on the street. The four major design elements are shown on this screenshot from his video presentation.
It’s an interesting idea, but how well will it work?
David Stanek and Charles Alexander put together a basic Vissim model to test out four variations of the concept versus standard intersection operation. You can read their whole paper Simulation Analysis of Intersection Treatments for Cycle Tracks to learn more.
The conclusion surprised me: The Protected Intersection with right turning vehicles to pedestrians/bicyclists significantly reduced motorist delay, slightly increased bicyclist delay, and slightly improved pedestrian delay with the overall effect of having 40 second of average delay vs. 51 seconds of average delay at a standard intersection. (see table below from the paper).
The overall conclusion is that Protected Intersections could be a significant improvement for an intersection with heavy bicycle/pedestrian use. Now we need to build one and field test it!
- Simulation Analysis of Intersection Treatments for Cycle Tracks
Note that this was NOT designed by Nick Falbo nor is it his idea. This is a very common Dutch junction and is well documented in the Dutch CROW manual for bicycle traffic design.
Nick took this from: https://bicycledutch.wordpress.com/2011/04/07/state-of-the-art-bikeway-design-or-is-it/
Which has been updated: https://bicycledutch.wordpress.com/2014/02/23/junction-design-in-the-netherlands/
Falbo did create a video that does a great job of communicating the design.
Also note that in The Netherlands it is often faster to progress through junctions on the cycleway than on the motorway though this does depend on signal timing.
Interesting news! Seems pretty expected, though, given that the Dutch have been experimenting with bicycle intersection design for decades, and this is the design they settled on. A number of protected intersections are under construction as we speak, and one has already opened, so you’ll get the chance to analyze them very soon.
Thanks for sharing our research. I wanted to provide a few notes of caution on the findings.
– The analysis results are for a particular set of motor vehicle, bicycle, and pedestrian volumes, so a different set of volumes will likely have a different outcome.
– The main source of delay savings was moving the bicycles out of the traveled way. With the slower bicycle traffic in the cycle tracks, motor vehicles were able to move faster. If less than 100% of the cyclists use the cycle track, then the delay savings would not be as great.
– A secondary source of delay savings was the shorter crosswalks, which allowed for lower minimum green times for the side street signal phases.