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Need for Open Sight Lines

by Art Mittelstaedt Jr., Ed.D, and Thom Thompson, MS, CPSI, playground safety consultant

From this viewpoint, areas of the elevated platform, the area behind the large tree and some of the fenced area (right) create obstructed sight lines.
Oxford Garden
Playworld Came America

The first consideration in the overall design and selection of equipment should be to assure that when the play site is completed there are no barriers to visual supervision.

The negative consequences to poor sight lines are a litany of preventable incidents:

  • In 1993 a two-year old girl was sexually assaulted in enclosed play equipment at the outdoor play area of a restaurant in Wenatchee, Wash.
  • In 2004, a four-year old boy was fatally burned in the tower of a fort-like outdoor play structure near Anchorage.
  • In 2006, a five-year old girl in La Habra, Calif. was sexually assaulted in enclosed play equipment at an indoor play center.

These are just three of over a half dozen incidents co-author Thom Thompson is familiar with. With the exception of the Alaska case, the incidents occurred in equipment with a fully enclosed design.

Playground safety is greatest with open sight lines within and outside the play area. Design of the playground should establish such sight lines. CAD drawings with placement of play structures and equipment (view from various angles) are helpful in designing playgrounds with open sight lines.
Adapted from Thompson T, Bruya L. Playground Supervision: An Essential for Children's Safety.

CPSC, logically, recommends open sight lines for the design layout of the play area and for the play equipment.
Play for All Guidelines, a best practices publication, advises: "Play areas should be visible to both parents and children...there must be no area hidden from view that could encourage or harbor deviant or criminal behavior..."

Specific recommendations are made:

  1. Fencing should define but be transparent. Two thirds of vegetative barriers should be open.
  2. All play areas should be visible from outside the area.
  3. Larger equipment should be placed so as not to block views of other equipment or areas.
  4. Spaces and equipment should be placed to allow sight over, under and around.
  5. Semi-enclosed spaces should have enough openings to see a child from any angle.
  6. There should be more than two direction of visibility into all play spaces from the surrounding area.
  7. Tunnels must be large enough for adult access and have two means of egress.

There are three types of locations that need special consideration: play areas at schools, parks and multi-family housing complexes. Day-care centers are not under consideration here, as they are not open to the public and subject to strict teacher/child supervision ratios.

The first consideration for a play area is topography. Small knolls, established wooded areas and great distances from a reasonable access to the site affect the suitability of the play area. Once these factors are addressed, the design and equipping can move forward.

School Play
Supervising children's activity and behavior on the equipment is the first concern and highest legal duty for school personnel. With outside barriers, it is particularly important some view from the surrounding neighborhood is maintained. Consideration needs to be given so that passing police surveillance from the street or parking area is not negatively impacted, which is clearly important during nonschool hours.

Equipment should be placed to allow sight over, under and around the play area. This play equipment and layout offer no barriers to visual supervising play activity.

Park Play
Public park play facilities have the same concerns as schools regarding equipment visibility and surrounding barriers to protect the site from hazardous environment conditions, such as traffic or unrestricted waterways, deep gullies or drainage ditches. Parks can present unique challenges for the L.A. or specifier because they often incorporate features only included in the best thought out school play sites. Park play design may incorporate berms, natural landscaping, plants and small retaining walls, which could obstruct views.

Landscape features that rise above the natural grade determine the placement of benches and tables. Plants have the same consideration. They are best used to define the perimeter of an area for age separation or as low interactive activity areas.

Retaining walls should be kept low or have a top that does not have a flat surface that serves as a balance beam. Some would require fall protective surfacing. If the wall makes a turn of direction it should be curved, or the short leg should be on the interior visible side of the play area so as not to create a hiding niche.

Multi-Family Housing Play Areas
Play areas by housing development companies are selected on the principle that the area is not suited to any money-making development, i.e., "junk ground." The play site should be in proximity to the most likely users. It should have the same direct and secondary supervision capabilities as those of schools and parks. The topography should not create inherent hazards to children. If the topography is not suitable, like a site with a 10 ft. drop in 70 feet, then adjusting the severe slope through terracing is the first consideration. Avoid a play area placed near one and two bedroom units. Residents here are likely singles or new couples. Place the play area near the three or four bedroom units where the residents are more likely to have children and parents to supervise play.

It is more likely the equipment here will be viewed from one angle by a parent on a bench, as opposed to someone walking around the structures. That means careful consideration of play equipment, such as no play panels on elevated platforms.

Barriers are a primary concern for these play areas. Because space is confined in a housing development, it is not unusual to locate a play area adjacent to a parking area. Such a location requires (ASTM F 2049) a fence to separate these conflicting activities. This is also supported by CPSC and the Play for All Guidelines. The barrier needs to meet the same criteria as for schools and parks for visibility sight lines, but with the added assurance that it is adequately protected from vehicular traffic.

ASTM is only just beginning to look at the issue of equipment sight lines. There is no consensus on how or even if the issue will be addressed. It is up to the prudence of the landscape architect or specifier to look carefully at the proposed equipment, sit location and layout to determine if open sight lines can be provided. There is a method we suggest for determining if equipment and the play area have sight lines that facilitate supervision from two or more points of view. This involves evaluating the site's major equipment pieces and proposed landscaping from the CAD drawings.

Equipment Sight Lines (viewed from CAD drawings)

  • Create a ground view drawing of the equipment looking north.
  • See if the components block the view to the south side of the structures.
  • Rotate the view 90 degrees east and west to see if views are blocked.
  • If views are blocked, rotate the equipment another 90 degrees, either from the second point of view or the initial north point of view.
  • If the third point of view allows sight to the opposite side, the equipment passes with a minimum two points of view for supervision.

Play Setting Sight Lines

  • Establish the most likely sightlines from the street, parking, entrance and neighborhood area.
  • Add all proposed site amenities, such as berms, plantings, retaining walls, etc.
  • Using a ground view evaluate the perimeter points of view.
  • See if site amenities and equipment block views.
  • Rotate the drawing 90 degrees and evaluate the new view for blocking sight lines to the opposite side of the play area.
  • If anywhere along the arc to the second 90 degrees point of view is unobstructed, that viewpoint passes.
  • Repeat the rotation to a second viewpoint and evaluate for unobstructed line of sight to the opposite side until a second sight line passes.

Note: When evaluating major equipment structures for multi-family residences, it might be helpful to establish the best single viewpoint and locate benches or tables with that sight line.For example, placing the structure at a 45 degree angle to the 90 degree perpendicular line of the site might be the best angle for single sight line supervision.

It is critical children be seen on playgrounds and that they are watched. There is a history of tragic assaults and fatalities that make open sight lines a reasonable, necessary consideration for site design.

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October 15, 2019, 5:18 am PDT

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