Obstacles

Obstacles are objects that are directly on the path of a pedestrian route, thus blocking the path. The ADA (Americans with Disabilities Act) requires a "clear floor or ground space" along accessible pedestrian routes. This allows pedestrians, especially those using walkers or wheelchairs, to remain safely on the sidewalk or crosswalk. Moving off the path to avoid an obstacle may be impossible or may cause imbalance, tripping, or other hazards. (ADA 305)

You should place labels at the base of the obstacle, which is any object that blocks a path. Placing a label any higher may make the lat-lng estimation inaccurate. Notice how the label on the lower left image that is not placed at the base of the tree has a lat-lng that is very far from the sidewalk (as seen in the mini map).

If there is a long stretch of construction, like in the example on the right below, you should place a temporary obstacle label at the beginning and end of the construction (in the same manner as in the Surface Problems section.

Severity should be higher for obstacles that cover more of the path, have less room for navigating around them, or would cause pedestrians that avoid them to put themselves into harm’s way (by going into traffic, going off the sidewalk, etc). There are more examples throughout this page.

A Street View image with a tree in the middle of the sidewalk
A tree in the middle of a sidewalk.
A Street View image of a long stretch of sidewalk under construction
A long stretch of sidewalk under construction.

You should use an Obstacle label on any permanent fixture that is placed in the direct path of pedestrian routes. This could also include extreme instances of overgrowth or poles that are located (even partially) within curb ramp flares. Below are examples with various degrees of severity.

A Street View image of a pole almost entirely out of the path, but it is still located in the ramp
Severity: 1. The pole is almost entirely out of the path, but it is still located in the ramp.
A Street View image of a street light pole in the middle of the sidewalk
Severity: 3. There is probably enough space to maneuver around.
A Street View image of a tree in the middle of the sidewalk
Severity: 5. There is no way to get around this obstacle without going into the street.

You should label temporary obstacles with the Obstacle label. Temporary obstacles are objects that are not part of the "built environment", such as construction, minor overgrowth, parked cars, and trash cans.

A Street View image of a trashcan on a sidewalk
Severity: 1. The trash cans only slightly blocks the path, and is easy to avoid safely.
A Street View image of leaves and foliage overflowing onto a sidewalk
Severity: 1. There is enough space for pedestrians to use the sidewalk without being blocked by the leaves.
A Street View image of overgrowth onto a sidewalk
Severity: 3. This does not leave quite enough space to maneuver around. This is also on the edge of temporary and permanent; overgrowth that is any more severe than this would probably be permanent. (this also requires a surface problem label)

Any objects that are not directly on the path of a pedestrian route (as in the first three examples below) should not be marked as obstacles. Things like moving cars and pedestrians are not obstacles either, so these should not be marked.

A Street View image of a pole almost entirely out of the path, but it is still located in the ramp
This pole is clearly not on the path of a pedestrian route.
A Street View image of a pole not on the path of a sidewalk
This pole is not at all on the actual path, nor on the curb ramp flare at all.
A Street View image of objects that are not obstacles, such as a trash can
This trash bin should not be labeled as an obstacle in path. It does not directly block the path of a pedestrian route, and is easily avoidable.
A Street View of a vehicle in motion
Vehicle in motion. Hopefully self-explanatory.

Even though obstacles in a crosswalk are not part of the sidewalk, they are part of the route that pedestrians are meant to follow, so you should label obstacles on a crosswalk in the same manner as other obstacles.