Parking Garage: Planning and Design
Number of Turns
Princeton Parking Structure Visiting Driver Analysis
For an unfamiliar driver, the sheer number of turns necessary in the search for an empty parking stall is a true indicator of garage efficiency. This translates into average speed, and so also the amount of time it takes a visitor to reach an empty stall. This is compounded by the one-way circulation, which means that the visitor will have to make extra turns to locate a vacancy.
For a driver not used to this garage, it will initially
INTROdUCTION
ar c G 6 9 1 t y p o l og y pat t e r n b o o k
be somewhat confusing because of the one-way are looking for the best location possible, it is necessary to drive around the ground floor before heading to the next level. Of course, this will then in turn slow down other traffic parking or unparkEntry path for unfamiliar drivers (Level 1)
ing on that floor. Typically, drivers entering a
fundamentals
direction. The driver will soon discover that, if they
garage move more efficiently because they only require the first available stall. But a visitor will
360ยบ turns
Because the visitor will be expecting to find a free stall by searching ALL the stalls in the garage, the number of complete turns is nearly twice that of the familiar driver. This can result in disorientation for the driver because their direction changes so often. Landmarks and signage are critical in garages with a circulation system that is not intuitive. At Princeton, the central ramp becomes a landmark for drivers.
drive slower, or wait longer for a stall, and thus cause congestion that familiar users do not
In the typical levels of parking, the circulation gets
types
expect.
more complicated: the visitor will pass some stalls more than once, which is good for accessing available stalls, and that is in the interest of this effect on circulation because the driver is on that level for longer, and their re-circulation interferes with vehicles entering and exiting the central
Stalls passed
ramp. The visiting driver can also be affected by the structure of the garage: a low floor-to-floor height can be discouraging and somewhat claustrophobic. It can also be uncomfortable for pedestrians, because the light fixtures are mounted between steel beams - this creates a dimmer interior which can translate into a feeling of insecurity. End of path for unfamiliar drivers (Level 5)
SOURCES
To a driver unfamiliar with the garage, every stall is a possibility - the relative turnover rate is not apparent. Therefore any location is an opportunity for vacancy, and more like than not the visitor will attempt to cover the area of the garage as thoroughly as possible in order to find an empty stall. The driver believes that the garage must have free stalls, therefore free stalls ARE expected. The one-way circulation requires the driver to then pass some stalls twice, which while increasing the opportunity for finding a vacancy, lengthens the time spent searching and so lowers the Level of Service.
PLANNING AND DESIGN
type of driver. However, this will have a negative Central path for unfamiliar drivers (Typical Level: 2-4)