The Role of Sight Distance in Parking Lot Safety

It is an intent for the civil engineering design of parking lots to include reasonable safety for the combined use by drivers, cyclists, and pedestrians.  In commercial centers, residential complexes, or public areas, an appropriately designed parking lot enables efficient vehicle storage and also considers safety in the design, construction, and maintenance to minimize risks associated with vehicular related accidents and other hazards.  One important component for the safe design of parking lots is sight distance.  Sight distance is the limit of visual field of view that is observable to reasonably attentive drivers, cyclists, and pedestrians, which provides the opportunity to identify possible hazards with time to react for accident avoidance.  There are three types of sight distance, that are common in roadway design:  intersection sight distance, stopping sight distance, and passing sight distance.  Adequate sight distance in parking lots is essential for improving safety and reducing the risk of accidents.  In parking lots it is essential for vehicles maneuvering in close proximity to pedestrians and other vehicles, that clear sight lines are maintained to prevent collisions and to ensure efficient traffic flow.  The layout design, and continued maintenance in the built environment, of parking lots should prioritize clear lines of sight at intersections, corners, pedestrian crossings, and entrances/exits.  Visual obstructions of pathways can reduce the available sight distance and thereby increase the probability of accidents.  Therefore, the design, construction, and maintenance of parking lots addresses the control of foreseeable blind spots.  This includes the placement of signage/pavement markings, use of artificial lighting where night use is expected, and the appropriate choice of landscape planting and maintenance.  In addition, the use and location of traffic control devices aides in insuring that drivers and pedestrians will be positioned to readily observe their surroundings and to avoid unexpected conflicts.  Clear and concise signage helps drivers anticipate curves, pedestrian crossings, speed limits, and other critical information.  Additionally, traffic calming measures like speed humps or rumble strips are a means to cause drivers to slow down vehicles, which enhances overall safety by giving drivers more time to react to their surroundings.

The configuration of parking spaces also impacts sight distance.  Providing sufficient space between rows and aisles allows drivers to navigate comfortably with a reasonable field of view.  The presence of tightly packed rows and/or excessively narrow aisles can limit visibility and make it difficult for drivers to recognize from a safe distance the presence of other vehicles, cyclists, or pedestrians.  This is of particular importance in busy parking lots, such as certain shopping centers, where vehicles frequently enter and exit along with the presence of high pedestrian traffic.

Maintaining sight distance includes regular maintenance of the parking lot infrastructure.  Poorly maintained signage or pavement markings, and overgrown vegetation or debris can limit visibility and create hazards.  Property inspections and appropriate repairs are necessary to safely address that sightlines are not obstructed and that the condition of the built environment remains clear of potential hazards.

Drivers and cyclists should be aware of their surroundings, yield to pedestrians in crosswalks, and follow the posted speed limits.  However, although vehicles customarily yield the right of way to pedestrians, the pedestrian has not been granted the right of way.  Therefore, pedestrians should be attentive during their approach of operating vehicles and when available should use designated crosswalks and walkways where pedestrian traffic will be expected.  

Sight distance is one important factor in the overall safety of parking lots.  Effective design along with the reasonable maintenance of vegetation, signage, and pavement markings assures the opportunity for vehicle operators, cyclists, and pedestrians to observe each other with sufficient time to avoid conflicts and injury.  By prioritizing sight distance, parking lot maintainers and designers contribute significantly to overall traffic safety and accident prevention.

If you have a matter involving a sight distance issue feel free to contact us to discuss.