The Case for Removing the Greenleaf Centerline - The Pasadena Example and Many Others...

Just received the City of Pasadena Neighborhood Traffic Management Program Community Handbook from a college friend. The handbook outlines Pasadena's very thoughtful and professional traffic calming program.

Those of you familiar with Pasadena, California know that it has residential neighborhoods very similar to Wilmette: classic 1920's housing stock, grid road layouts, etc. So I would regard this as highly relevant.

Here is the official policy on "Markings/Striping Changes - Removal of Centerline on Residential Streets" from page 22 of the pdf file (page 17 of the handbook):

Centerlines can provide drivers with clear delineation of travelways. On residential local streets that are relatively narrow (36’-42’) with low traffic volumes, centerlines may induce speeding because drivers’ travelways are clearly delineated. Experience has shown that the removal of centerlines on local streets results in more cautious driving behavior. Painted edgelines have a similar effect. Edgelines visually reduce the width of the roadway causing drivers to be more aware.

Interesting.. so it's official City of Pasadena policy (based on experience and empirical data on traffic safety) to remove centerlines when painting edgelines on local streets that are 36'-42'. Above is a picture of Greenhill Avenue in Pasadena - a street that has been visually narrowed with edgelines without a centerline.

Our Greenleaf Avenue is 38'. Yet our Transportation Department believes that centerline removal is somehow radical and unsafe.. and could not articulate any data supporting this theory at our last meeting.

Also note that "Community Involvement" is the first step in Pasadena's process. That's a novel idea. :-)

The Pasadena example is just one example.

Here are examples in Maryland at the following link on the ITE (Institute of Traffic Engineers) website: "Both Anne Arundel and Howard Counties have painted parking lane lines WITHOUT centerline striping on residential streets. This visually narrows the available roadway and has resulted in reductions of 3mph to 4mph in vehicle travel."

There is a thoughtful study commissioned by the Wiltshire County Council in the UK that shows a 33% reduction in accidents due to centerline removal on 12 different roads. Below is a street scene of one of the examples:



Below is another successful example of centerline removal in Geneva, Switzerland:



The list goes on and on and on...

Furthermore the Manual on Uniform Traffic Control Devices from the US Department of Transportation Section 03B-01 states:

Centerline markings should be placed on paved urban arterials and collectors that have a traveled way of 6.1 m (20 ft) or more in width and an ADT of 4,000 vehicles per day or greater. Greenleaf has less than half that ADT.

Where is the proof that eliminating the centerline on Greenleaf would present a hazard? I don't see it. If anything, it's the opposite.