Sunday, July 10, 2011

Delft Bike Lane and Bike Box or Crosswalk

Bike lane striping with a right turn slip lane for vehicles to the right
I originally thought this was a bike box, but on further reflection, it appears to be a bike lane with a crosswalk colored the same as the bike lane that is developed.
This was in Noord-Oude in Delft Bike lane with Bike Box and Right Turn Slip Lane Example

The following text is excerpted from the Northeastern University student report which can be found here.The CROW manual recommends the following for intersections with mixed traffic [2]:
  • "Cyclists are kept within the motorists' field of vision"
  • "Where possible, conflicts are bundled so that an unambiguous situation is created"
  • "Cyclists having to make illogical movements at intersections or being diverted around intersections must be avoided"

Bike Box

Striping for the Copenhagen left is just starting to come to view
One solution the CROW manual uses is an Expanded Cycle Stacking Lane (ESCL), which are known as Advanced Stop Lines (ASL) in Great Britain and as bike boxes in the United states. Bike boxes are designated stopping areas at the stop line of a signalized intersection where bicyclists can queue and wait for a green light in front of waiting automobiles. The CROW manual recommends using these at the following intersections [2]:
Bike box with the Copenhagen left (turn box to the right of the through traffic )
  • Intersection with traffic control system
  • Inside well developed (built-up) areas
  • With a relatively large number of cyclists turning left
  • At well organized intersection
  • With combined traffic or cycle lane on carriageway
  • Maximum two lanes/stacking areas per approach road
Looking to the left while standing in the bike box
(pedestrians completed their movement in a not so well defined crosswalk)
The manual recommends these bike boxes are marked with a bicycle symbol, colored red, and be separated from a left turn lane for motorists. The introductory cycle or refuge lane is also recommended to be colored red. The depth of the stacking area should be 4 to 5 m (13.1 to 16.4 ft), with a width equal to the motorized traffic lane plus the introductory cycle lane. The introductory cycle lane should be at least 25 m (82 ft) long (reference p. 265 for additional dimensions). NACTO provides recommendations for bike boxes in the United States, and requires a 10 to 16 ft (3 to 4.9 m) deep bike box with bicycle symbol. In addition it recommends the bicycle box be colored. For more NACTO recommendations click the following link

There are several advantages to utilizing bike boxes. Most importantly, by having bicyclists wait in the front and center of an intersection in front of cars as opposed to the far right side, they become more visible to motorists in any direction, a key to increasing cyclist safety. Also, by using bike boxes to give priority to cyclists at a busy intersection, they will have the opportunity to quickly and safely enter and clear the intersection before automobiles have the opportunity to do so. Cyclists in the bike box will be exposed to less nuisance from exhaust fumes because they will be in front of cars.

[Two-Stage] Left Turn Bike Box

Another type of bike box is a marked waiting area on the right of the road for cyclists turning left at traffic lights. The CROW manual recommends these for areas with max speeds of 60 km per hour (37 mph) in lieu of a the left hand turning pocket lane. (CROW page 264.) This bike box should have a width of at least 1.2 m (3.9 ft) and requires an additional traffic signal for turning bicyclists [2]. NACTO recommendations are very similar to the CROW's, and can be found at the following link. Our first experiences with left hand turn bicycle boxes in the Netherlands led to confusion on how to access them when approaching an intersection. Improved signage and road markings would make these a more intuitive bicycle facility.

Click the link below for examples of effective and and less bike boxes in the municipality of Delft, Netherlands.
Bike Box Examples

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