Delaware Shade Tree Commission discusses street corner sight “triangles”


By Gary Budzak - gbudzak@civitasmedia.com



A corner at William and Sandusky streets — at City Hall — is shown to illustrate a “sight triangle.” City code states that street corners should have a clear sight triangle of 20 feet from an intersection.

A corner at William and Sandusky streets — at City Hall — is shown to illustrate a “sight triangle.” City code states that street corners should have a clear sight triangle of 20 feet from an intersection.


The question of whether some trees in the city of Delaware are too close to an intersection was discussed at the city’s Shade Tree Commission meeting on Tuesday.

“It’s a frequent complaint of residents,” said Assistant City Engineer Jennifer Stachler. “We have a lot of calls to see clearly at an intersection, due to trees or other obstructions.”

The issue balances safety with preserving the more than 15,000 trees in what the city calls its “urban forest.”

Delaware city code has a section on “Visibility at Intersections,” which states: “In any district on any corner lot, no fence, structure or planting shall be erected or maintained within a clear sight triangle formed by the right-of-way lines of two intersecting streets, and a line drawn between two points, each measuring twenty (20) feet from the intersection of the right-of-way lines.”

In other words, a motorist should be able to have a clear line of sight for 20 feet on either side of a street corner, which would form a triangle if those three points were connected.

However, Stachler told the commission “there was no basis for what was in the code. … We need to apply an accepted standard, based on engineering principles.”

One such standard is from the Ohio Department of Transportation. In its “2012 ODOT Highway Design Manual,” it said that trees can be placed within an intersection sight distance triangle as long as at least 50 percent of an approaching vehicle remains visible. “If 50 percent or more of the vehicle were hidden behind a vertical curve, it would not be appropriate to further reduce visibility by planting trees,” the manual said. Other considerations include the height a tree’s limbs clear the road, and the distance from a tree trunk to the road.

During the public comment portion of the meeting, Jeff Strung, the director of planning and landscape architecture for civil engineering firm EMH&T Inc., told the commission the ODOT standards were more for rural highways.

“Our clients see the value of street trees,” Strung said. “No other community applies the ODOT standards to local street intersections.”

Another sight triangle was suggested, based on the distance traveled in one second at a roadway’s speed limit.

There is also a section of Delaware city code on “street tree planting requirements.” It says that developers will plant “hardy, long-lived shade trees” for every 40 feet of frontage along each road, at “an adequate distance from intersections so that at full maturity,” the trees allow for unobstructed visibility.

Parks supervisor Stacy Davenport said Stachler would research what other local communities are doing, and come up with a common-sense recommendation for City Council.

“We’re here more to begin this discussion,” Stachler said. “At this point, we’re just looking for input.”

A corner at William and Sandusky streets — at City Hall — is shown to illustrate a “sight triangle.” City code states that street corners should have a clear sight triangle of 20 feet from an intersection.
http://aimmedianetwork.com/wp-content/uploads/sites/40/2016/01/web1_DSCF7445.jpgA corner at William and Sandusky streets — at City Hall — is shown to illustrate a “sight triangle.” City code states that street corners should have a clear sight triangle of 20 feet from an intersection.

By Gary Budzak

gbudzak@civitasmedia.com

Gary Budzak may be reached at 740-413-0904 or on Twitter @GaryBudzak.

Gary Budzak may be reached at 740-413-0904 or on Twitter @GaryBudzak.