Removal of Trees from Traffic Circles

Rob Wrenn
Monday July 30, 2018 - 11:05:00 AM
Traffic Circle Design Specifications from Bicycle Plan
Traffic Circle Design Specifications from Bicycle Plan

Dear Mayor Arreguin and members of the Berkeley City Council,

I was shocked to learn that city staff, with little notice and no public discussion, are planning to remove all trees from the city’s traffic circles and take over maintenance of the circles.

I ask that the Council take action to put a halt to this rash, ill-considered and draconian plan and instead undertake a careful review and evaluation of traffic circles with an eye to setting reasonable standards for their maintenance. Neighbors of the circles should continue to play a role in their maintenance, wherever there are neighbors willing to do so.

Any plan for traffic circles should first be referred to and reviewed by the Transportation Commission, which advises the Council on traffic calming policies. To evaluate the impact of traffic circles, collision data should be collected and analyzed. I have seen no evidence that the city staff’s plan to remove trees is based on any data. Individual anecdotes about accidents should not be the basis for staff action, which should instead be based on comprehensive data and analysis. 

Comparing collision data from a ten-year period before installation of a traffic circle with data from ten years following installation would be helpful. The City has assembled collision data for various studies and plans and it’s not hard to do. Traffic circles are intended to slow down traffic and should reduce collisions. Has this occurred overall? Do trees make a difference? Intersections with traffic circles and trees could also be compared to other intersections with similar traffic counts and no circles. To the extent that any baseline data exists, it would be useful to know whether traffic circles result in reduced volumes of traffic or lower travel speeds. 

The City staff should also look at the effect of stop signs at traffic circles. Some circles have four-way stop signs, some have two-way stops. Confusion can be caused if one traffic circle has a different stop sign set up than the next circle on the same street. 

Properly maintained trees in traffic circles do not significantly interfere with visibility (see photo above). In some cases, lower branches need to be trimmed, but it is definitely not necessary to remove the trees. The city’s newer signs, put in to replace the signs originally in use, are more of an obstacle to visibility given their height and placement, than the tree trunks are. Tree branches and leaves shouldn’t be an obstacle if trimmed to an appropriate height. 

The City’s recently adopted bicycle plan calls for more traffic circles. The plan contains an illustration of a circle (on page f-35 and above) that includes a “broad canopy tree”. The plan calls for circles to be “maintained to preserve sightlines”, but this clearly does not preclude having a tree in the circle. San Francisco’s guidelines for traffic circles actually encourage planting trees in circles. 

Trees have enhanced the appearance of traffic circles and of the streets where they are located. They are a neighborhood amenity. Removing all trees because some trees may need trimming to improve visibility is like throwing the baby out with the bath water. Don’t throw the tree out with the branches that need to be trimmed. 

The traffic circles in my neighborhood were installed at the request of neighbors, after votes were taken showing majority support. Most included trees. In 2005, the City did a survey, asking: “The City has installed 30 new traffic circles in residential neighborhoods around town to calm traffic. Do you think they are an effective tool to slow traffic and improve safety?” 43% answered yes; 23% said somewhat; 23% said no; and 9% didn’t know. 

The city should have a goal of ensuring that circles with trees and other landscaping are designed, signed, and maintained to work well for pedestrians, bicyclists and motorists. This is something the Transportation Commission and staff could work on. 

I also don’t think it’s realistic to think that the city staff could fully assume responsibility for maintenance of circles. It would be appropriate for staff to check circles periodically to ensure adequate visibility, but city staff are not able, as it is, to keep up with the maintenance of all the public right of way, landscaped areas and green spaces that they are responsible for. Things will work better if wiling neighborhood volunteers continue to help with maintenance. I think traffic circles, esp. those without trees, would look shabby before long if the city were solely responsible for their maintenance.