Posts Tagged ‘Intersection Design Toolkit’

©Photograph by H-JEH Becker, 2012

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Some more comments from the recently completed 72 day, 4,100 kilometres cycling touring trip through the States of Montana, Idaho, Washington, Oregon, and California with the southern terminus being Santa Barbara.


Bend OR, Traffic priority sign, Motorists yield to cyclists©Photograph by H-JEH Becker, 2012

Bend OR, Traffic priority sign, Motorists yield to cyclists
©Photograph by H-JEH Becker, 2012

Especially in intersections, trip time, visibility to motorists, separation of cyclists from motorists, and awareness (to both motorists and cyclists) of where one should cycle and where one could expect cyclists are some of the key factors to attract people to cycle rather than to drive. Completeness of a cycling network, and opportunities for combined mobility trips are the others.

These are some of the factors that active cycling cities in Europe with high cycling mode share have incorporated into their cycling infrastructure and networks.


Cyclists’ visibility to motorists; separation of cyclists and motorists especially in intersections and supporting trip time

Research has shown trip time as an important factor that will influence people to use bicycles for trips or to use other transportation options instead, such as driving a car.  Current emerging technology has the capacity to reduce green phases of traffic signals to length of time that is just sufficient for the crossing of an intersection by traffic, including cyclists and pedestrians.  This trip highlighted the rapid rollout of this technology.

This technology could also be installed at intersections of neighbourhood cycling streets (bike routes or as Portlanders like to call them – bike boulevards) and either collector or arterial roads providing reduced trip times for commuters enjoying these quieter streets.  Vancouver BC has shown the effect on cycling traffic growths on neighbourhood cycling streets with cyclists-activated traffic signals.  Now this technology can reduce the waiting time for signals to turn green for cyclists.


Traffic Signal Timing

The type of traffic signal monitoring system used and its efficiency in changing signals when there is no traffic on cross streets has a great effect on cycling trip time.  As an example, if one needs to pass through 10 signalized intersections in a 30-minute trip and timing sequence is such that 30 seconds are wasted at each intersection, then the trip time is lengthened by 5 minutes or by 17%.  The constant need for stopping at signalized intersections on the red phase and needlessly waiting when there is no cross-traffic is enough to question ones dedication to making trips by bicycle.


Of course, the same is true if routes are on local streets and stop-signed intersections are frequently located along the way.  Vancouver BC has shown the effect of growth of local neighbourhood cycling routes when cyclist-activated traffic signals are present at arterial and collector road crossings.  Now, how much more efficient would trip time be if these signals were controlled by video camera or other technology sensors that track traffic movement and only change the light phase to allow traffic to cross.  Car traffic trip time would decrease while street carrying capacity would also increase.  Drivers’ and cyclists’ frustration levels at intersections would go down.

In 2006, a colleague and I cycled from Vancouver BC to Chicago stopping in Madison WI for the Pro Walk Pro Bike Conference.  Along the way we passed through a mid-west town with 10 traffic lights along the main route through it.  I was able to pass through all the signalized intersections without needing to stop and put my foot on the pavement.

As I was approaching the first light, there was a car stopped at the intersection on the crossroad.  Just as I was approaching the stop line, the lights changed allowing the car to proceed through.  For some reason I decided to hesitate on the bicycle before putting my foot down.  The hesitation was only for a few seconds, maybe two or three.  The car had cleared the intersection.  Before the left foot went out of the pedal’s foot strap, the light turned to green and I continued to cycle.  This happened over and over again as I cycled through town.  At one intersection there were two cars backed up on the crossroad.  The green phase stayed on long enough for the two cars to clear the intersection and then the light turned green in my direction.  The length of the green light phase depended on the number of vehicles backed up.

A very efficient system it was.  Cars and trucks were only held up long enough for vehicles on the cross street to clear the intersection.  There was no dead time in any signal phase.  The amount of gasoline wasted by cars at intersections was limited to the minimum.  So was the production of greenhouse gas and the amount of car produced gases that drivers inhaled.  The lights turned only when there was a need.  The monitoring mechanisms of the signal systems, which looked like video cameras, picked me up as I cycled to intersections.

On the cyclotouring trip is year I encountered these efficient traffic control systems in many towns and cities in the mid-west.  The technology is spreading quickly.

Bike Lanes Approaching Intersections.  Continuing through intersections???

In this trip it was still evident that the old design approach of “stopping a bike lane when the road design becomes difficult” is still very much in vogue despites the learning from European cities success in growing their cycling mode share significantly.

Visibility to motorists especially in intersections, separation of cyclists and motorists, and awareness (to both motorists and cyclists) of where one should cycle and where one could expect cyclists are some of the key factors to attract people to cycle rather than to drive. 

There were encounters of intersections where cycling lanes led up to signalized intersections and with very few encounters of cycling lanes marked through intersections.

Some cities have started to be more progressive in intersection designs that would appeal enough to non-cyclists, such as motorists, to try cycling instead.

Portland is one example.  Now, a few coloured bike boxes have been installed to facilitate left turns and to give cyclists a bit of a priority to clear intersections before car movement.

Separation of Cyclists and Motorists

Separation is one of the quickest ways to grow cycling traffic yet it is still infrequently used in North America, especially in intersections.  Unfortunately some efforts at separation in intersections with roundabouts has increased cycling trip time and reduced safety as cyclists’ road vision and cyclists’ priority to other modes has been reduced.

We have all experienced cycling traffic growth on bike trails along waterfront or on operating and abandoned rail lines.  Separated bike lanes are an implementation of bringing almost the same cycling experience onto streets with the same result, significant cycling traffic growth.

Separated bike lanes were infrequently encountered on this trip.  In Eugene, one of the suburbs had a separated bike lane of the Danish cycle track design for several blocks before degrading to bike lanes.  The issue of how wide should a cycle track be came forth considering weather factors throughout the year.  A cycle track with the width of a normal bike lane was installed under deciduous trees that were carpeting the track with leaves during wet autumn weather.  As I was travelling over it there was some concern if the tires would slide out and I would plunge over the curb into the street with its oncoming traffic.  Certainly, wider cycle track would make less determined people give cycling a try.

Roundabouts or Smaller Traffic Circles

Coming from a city that has eliminated stops signs at many intersections by installing traffic circles at 200 or 300 intersections, disappointedly not many were seen on this trip.  Eugene OR had an interesting design which addressed the perpetual issue of motorists shortcutting the traffic circle and ending up in the direction of oncoming motorists and cyclists.  Portland OR enhanced a larger traffic circle through highlighting where cyclists may be through use of sharrows.

On a previous trip from Vancouver to Chicago back in 2006, I stopped in the City of Davis CA on the way back.  There I encountered a traffic circle for cyclists only at the intersection of two bike paths.  Cycling efficiency was addressed in the similar manner as the Eugene traffic circle.  Obstacles were placed in the way of cyclists to reduce shortcutting in the traffic circle.  Forward thinking is the design.


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