Parking Lots Traffic Flow

[RememberMe]

Angle parking at 71°
What would be the minimum practical one-way aisle width?
I'm trying to live with 15'

I understand that this can vary from one jurisdiction to another, my concern however is operational! Can cars get in and out of these stalls with a 15' wide aisle with relative ease, and is anyone aware if such tight dimensions have been allowed anywhere before?

Thanks a lot!

 

[IRstuff]

That seems awfully tight. The Honda Odyssey has a 16.75 ft length and 6.33ft width, resulting in a 17.9 ft diagonal. The Ford Excursion has 18.8 ft length, with nearly 20 ft diagonal.

Assuming a typical parking slot, vehicles tend to stick out beyond the striping, so there would be insufficient room to turn the car as you back out.

TTFN

 

[trafficPro]

The aisle width is very tight. It would be inadequate for nowmal width parking spaces. Even with a 10 foot width it is probably too small.Going to a wider parking space is a possibility, if the lot constraints mandate the narrow aisle. Another option would be to go to a different angle.
TrafficPro

 

[RememberMe]

IRstuff and trafficPro thanks a lot for your responses. As a result of your input the above parameters were modified as follows:

Stall: 8.5'x18'
Angle: 65°
Aisle: 17'

Still tight! However, was able to document these parameters as acceptable minimums! Based on geometrics and experience would you consider these new parameters as acceptable operationally!

Again thanks a lot for keeping these discussions lively and prompt!

RememberMe

 

[IRstuff]

If this is Japan, no problem ;-)

If this is the US, BIG problem. Stall width of 8.5 with perfect positioning leaves only 2.2 ft with the aforementioned Odyssey. Most people cannot routinely park with more than 1 ft accuracy, which would mean that probably at least half the time, the driver side door would wind up inaccessible. A 9 ft width is probably as narrow as you can go, if you're allowing full-sized vehicles in the stalls.

Likewise the question of stall length. Are the aisles alternating direction or same direction? Also, are there barriers or is it possible for a car in the facing stall to be parked into your stall? This happens a lot for facing stalls.

Is the 18' the driver side length? Does this mean that the passenger side dangles into the aisle?

The aisle width of 17 just looks way to difficult, unless that's the goal ;-). A 20 ft aisle seems to be the right size.

TTFN

 

[RememberMe]

Hi IRstuff,

The lunch I owe you is getting bigger, hope you're in NJ so we'll make it a sushi lunch and take advantage of less restrictive Japanese standards.

A little background, the stall sizes are existing and have been for some time with no reported problems! The existing layout utilizes 90° angle with 24' aisle width to allow for two way traffic!

The concern as for clearances between parked cars within the stalls was never an issue!

The modification was to use angle parking so we can reduce aisle width! Municipalities in the area allow 18' width for compact cars at 60°.

The aisles are not staggered but so is the existing configuration!

The concerns you're raising are well taken but it's extremely hard to go and tell somebody who has had them all these years that they don't work! So in that respect the situation is not changing!

The concern I would have is getting in and out of the stall! At worst the driver can back up straight at his 65°
angle. The 17' aisle will allow him 18.75'. I grant you that it's tight, but it's tight to start with. My concern would be for the in- and out- movement and the numbers are telling me (at least theoretically) that we have this 18.75'. If we resolve that we can live with the size of the stall can we reach the same conclusion for an isle width of 17'? TA

RememberMe

 

[IRstuff]

Sorry, I'm west coast, so that might account for my bias, since west coast tends to go for bigger cars.

The existing aisle width seems to be quite comfortable.

I can only assume that those with larger vehicles have already figured out what a pain it is to park there and either don't, or only drive small cars when they have to park there.

Cars that are shorter than about 15 ft should be able to do it if cars of similar length are parked there. I pity someone surrounded by F350's or Ram3500's, though.

TTFN

 

[RAWeber]

Have you laid out the entire parking lot with the angled parking yet? You may find that this entire discussion is academic. I have found that only with certain restricted geomitries to I get more spaces from an angled parking layout than 90-degree head-in parking.

There are generally two reasons for this - this first is that the steeper the angle, the more linear distance the space takes up. For discussion, lets use ten foot spaces. A 90-degree space takes up ten feet of curb. A 71-degree space takes up over 10.5 feet. As the angle steepens, the curb width increases.

The other reason that you lose spaces with angle parking is that often there is a loss at the end of the aisles that is greater than with head-in.

Good luck,
Robert Weber, EI
Maurer-Stutz, Inc

http://www.maurerstutzinc.com

"I am satisfied that your answer is correct. I am not, however, satisfied that your answer is right."

 

[RememberMe]

Hi RAWeber,

Angle parking is going to give you less parking spaces per row, you are certainly right there!

The gain comes from the reduction in the aisle width. With 90° parking your aisle has to accommodate 2-way traffic, while with angle parking your aisle will be handling traffic in one direction only. The net result is that you'll be able to fit more rows with angle parking than with 90°, resulting in a net gain if you choose the proper angle and if you have enough depth in your lot.

You lost me on your last comment between "correct" and "right", unless you intended a pun with your right meaning right angle!

I was able to document the use of such tight parameters by a certain municipality, if that interests you I could dig up the information for you!

Thanks for your response!

 

[trafficPro]

RememberMe
These dimensions are OK for a parking facility without much hour by hour turnover. Not good for a shopping center. OK for an office building. Many of the above insights are correct. You should look into whether the parking spaces head in to a wall or fence or interlock with the next aisle.

I know this forum is ID free. however, if you feel the need for more exploration of dimensions, angles, etc. I have a self designed interactive chart that calculates the dimensions needed, given the ones chosen. Either list your e mail address and I'll send it, or lets set up a meet at a NJ site such as Penn Station Newark, and I will give you a disc.

Traffic Pro

 

[RememberMe]

Hi trafficPro,

That's most generous of you! I would certainly like to meet with you if for nothing else other than to thank you for your participation, insight and "agreeing with me"!!!

My e-mail is: where_the_buck_stops@yahoo.com

Please contact me and we'll work out the details! Thanks again.

BTW this application was for an office building!