Parking lot design specifications
Parking lot design specifications
(OP)
I have become enraged at the design of parking lots for nearby shopping centers/malls/etc. during the pre-Christmas shopping frenzy. After contemplating a while and consulting with a few other people, I have come to the conclusion that there is no such thing as a well-designed parking lot.
I know this can't possibly be true.
I set out to search the web. I found a few design mandates from the government in the form of the ADA Guidelines, a few specifications for asphalt bases and ground pre-conditioning, and that everything should have a 1/4 inch-per-foot grade for drainage. There was very little publicly-available information on this topic, only a few references to things such as Architectural Graphics Standards and asphalt manufacturers/associations. (the best thing I see: www.apai.net, Design Guide, Ch. 5)
Does such information exist at-large, or is it confined to trade publications/texts? If it does exist, pointers would be gladly accepted, i'll be putting up a reference page with everything I can find on parking lot design, traffic flow, etc.
Also, if anyone knows a "good" parking lot in the DC/MD/VA area, i'd love to hear about it.
I know this can't possibly be true.
I set out to search the web. I found a few design mandates from the government in the form of the ADA Guidelines, a few specifications for asphalt bases and ground pre-conditioning, and that everything should have a 1/4 inch-per-foot grade for drainage. There was very little publicly-available information on this topic, only a few references to things such as Architectural Graphics Standards and asphalt manufacturers/associations. (the best thing I see: www.apai.net, Design Guide, Ch. 5)
Does such information exist at-large, or is it confined to trade publications/texts? If it does exist, pointers would be gladly accepted, i'll be putting up a reference page with everything I can find on parking lot design, traffic flow, etc.
Also, if anyone knows a "good" parking lot in the DC/MD/VA area, i'd love to hear about it.





RE: Parking lot design specifications
Most traffic flow issues are related and controlled by area departments of transportation (particularly if the lot feeds a state road). The drainage may be impacted similarly. As for traffic flow within the lot, that depends typically on three groups...the owner (or owner's architect), the local land planning agency, and the civil engineer. The ADA plays into this, but is accommodated pretty easily under most reasonable flow scenarios.
The number of spaces is dictated by land planning codes/ordinances. The type of spaces, except accessible spaces, is also dictated. From there, the geometry of the lot is usually decided by the architect to complement the building. The civil engineer then takes the hand he's dealt and plays his game for space layout, islands, traffic markings, drainage, etc.
Long way to answer your bottom line question, huh? The bottom line is that parking lots have no universal design criteria and are often subject to local whimsey and the capability of the civil engineer.
RE: Parking lot design specifications
Well - in New Jersey at least - usually each town has its own standards in the ordinance.
Parking spaces vary anywhere from 9'x18' to 10'x20'.
(There is also a practice that I think is being discouraged of having "compact spaces" like 8'x17' marked and designated for "compact" cars)
The typical standard around here for an aisle width for two way traffic, perpendicular spaces, is 24'.
I can't think of one publication that has everything you want - but here are some references
1- New Jersey Residential Site Improvement Standards (Free online - can't find it at the moment, I can email it to you if necessary)
2- Civil Engineering Reference Manual (CERM) by Lindeburg (not free)
My previous boss used to refer to cross slopes in parking lots greater than 5 or 6% as "door slamming" slopes - meaning your car door will slam shut when you get out.
Hope this helps a little!
Kate
RE: Parking lot design specifications
KRS Services
www.krs-services.com
RE: Parking lot design specifications
The ADA sets the max at 2%. Where I live, slopes of 0.5% to 1% are common (Southeast US, coastal plains).
Stay with common sense and engineering judgment...they usually serve one pretty well.
RE: Parking lot design specifications
Two reference manuals from the National Parking Association are found here -
http://www.npapark.org/08_pubs_01.html
There are multiple sites in the "parking" section of
http://www.trafficlinq.com/
A brief intro to parking lots can be found here
http://www.webs1.uidaho.edu/niatt_labmanual/
The ITE (Institute of Transportation Engineers)has several books in their bookstore at
http://www.ite.org/bookstore/pubsalpha.pdf
Check out "parking under p" but there are 59 pages of books and stuff.
Everyone has given you good advice. There is the traffic flow aspect, the drainage aspect, the landscaping aspect, the ADA aspect and the user friendly aspect (a snow removal aspect up north). This is an evolving field and we now have higher expectations of parking lots. However, during the Christmas season, parking lots are at peak capacity, drivers are running red lights and behaving badly.
Clifford H Laubstein
FL Certified PE #58662
RE: Parking lot design specifications
I like "trees and bushes and flowers and things" but, this is a monster. It must have been written by the landscape lobby! In all cases, it requires planting islands in the parking lot, no matter what size the lot is. In this part of the country, where we get snow in the winter, the islands are real plow breakers when trying to clear out the snow. Yes, trees are nice, but how about some practicality in these things too?
RE: Parking lot design specifications
Great sites, good references. I'll be posting some info to http://www.dullsville.com/parking.php sometime this week, with this info and others that I have found.
And, as Mr. Laubstein said, road rage (or mall rage?) peak season is now past, so it's not nearly as pressing. I'm off to the local library to see what they have from the ITE list.
RE: Parking lot design specifications
Check out parking garage design for the concept of LEVEL OF SERVICE as it applies to parking garages, many items as applicable to parking lots. Size of spaces, drive isles, slopes, radii, etc.. (I learned about the 6% slope rule for older drivers and vehicle door control while studying garages, the 10% rule for pedestrian walkways, the 12% rule for fork lifts and the 16% rule for older drives on ramps. I live and design in Central Florida and slopes under 1%-2% are the norm)
Remember, that people must walk from the parking space to the building entrance and pedestrians must cross the driveways at the property line on the sidewalk in the public right-of way. Think pedestrian safety.
Think about visibility triangles at intersections, not the 15'x15' zoning crap, but your local DOT "Green Book" (Manual of uniform minimum standards for streets and highways) requirements.
Remember the "clear zone" concept from the "Green Book". Keep trees & signs a minimum of 2.5' off the edge of pavement for driveways. Also think about throat depths and deceleration lanes.
For trucks, think compound radii. Design for tired, lazy truckers or you will be replacing curbing, trees, signs, bushes, etc.
Follow the MUTCD for all traffic control. Use yellow lines to separate opposing traffic. Use standard signage.
Sure, any engineer can design a parking lot. Just follow your local zoning regulations and common sense. How many can design a good one?
Clifford H Laubstein
FL Certified PE #58662
RE: Parking lot design specifications
To do so would result in an excess of parking spaces during most of the year. It would also incur excess drainage problems, as well as being wasteful of the land area, (an asset).
The design lot capacity is intended to meet the 30th highest hour. So dont be surprised if Christmas shopping parking is a bear. The inability to find parking almost immediately results in either a tedious circling of the lot, or a move to another commercial facility.
An unsafe design, on the other hand can cause pedestrian accidents, and fender benders.
Also understand, if the lot you are in is crowded on Christmas, so is the lot you are thinking of switching to.
If possible, design the facility so trucks and cars dont mix much. Also, due to building rear setback requirements, many designs feature parking in the rear of the buildings. They count towards your ordinance requirement, but dont help the site at all. Unless owner operated, most large stores do not allow employees to use rear exits, as shoplifting concerns mount. Examine the large commercial centers in your area. Take a look at the parking spaces delineated in the rear of the building. Most are almost totally devoid of parkers.
I've been reviewing commercial developments for planning board for years, and the towns that take my advice dont permit the counting of rear parking spaces over 5% of the total required. Even that was a compromise.)5 would have been better. If special circumstances indicate that rear parking would be used due to open passages thru the buildings, then the board has the option to permit the counting of those spaces.
TrafficPro
RE: Parking lot design specifications
cheers
Dan..Ireland