JUNE 2009 • PARKING WORLD • www.parkingworld.com16

Why Simple Design is Often ComplexHE INTENTION OF THIS TWO-part article is to describe the path adesign process usually takes in order toarrive at a desirable product – a user-friendly car park – and to present an

overview of some relevant factors that influence theprocess of functional design of any parking facility.

The Car and the Parking FacilityAs we all know, there is no such thing as free parking. Park-

ing costs money and someone has to pay for it. In one way oranother, it is the end user of the space who pays for parking,whether it is directly in the car park, via a lease for theoffice/shop, or indeed in the prices of goods sold in the shops.

In this article, the term “commercial parking operation”relates to car parks where a fee is charged directly to the user ofthe parking facility.

As illustrated in Exhibit 1, car park design is subject tonumerous considerations, some of which affect the designprocess more than the others. Broadly speaking, car park design

BY GEORGE M. BURTON

T needs to take into account user, functional, environmental andother considerations.

User considerations are presented in the viability of a carparking development and, as such, are a prerequisite of the designprocess. Determination of the car park viability entails a ParkingDemand Analysis and a Commercial Feasibility Study.

Assuming that the parking demand analysis concludes thereis a need for parking supply, then the results of the commercialfeasibility study will determine whether the functional designprocess shall be instigated or not.

Functional considerations are directly affected by thecriteria of user friendliness and indirectly by environmentalconsiderations.

However, environmental considerations directly relate totransportation, and therefore to parking as a whole, in theirpursuit to improve air quality and to alleviate traffic conges-tion. The car, being an essential utility, is a target of environ-mental concern.

The role of mass transportation is limited to areas of highpopulation densities. It essentially moves people between twopoints. However, people depart from that and scatter in alldirections.

Therefore, the car will remain an integral part of the trans-portation system and continue to be its primary mode.

Consequently, car parking is and will remain an essentialpart of all civic, cultural, social, business and shopping activities.People conducting these activities generate parking demand,which must be responded to with sufficient, effective and effi-cient car parking facilities.

Simple Design = Simple ManagementCar parks are the normal and natural termination points for

access roads and city streets. However, they are not the end of ajourney. They act as an interchange where a person goes frombeing a motorist to being a pedestrian. Hence, car parks mustbe functional and meet the needs of both motorists and pedes-trians. How efficiently the car park receives, stores and dis-charges cars determines its usefulness to its developer and thecommunity it serves.

Simplicity and ease of parking are the basis of good func-tional design practice. The design must provide for traffic circu-lation and parking manoeuvres in a safe and expedient manner,with minimum delay and no hazard to the safety of vehicles andpedestrians. The design also must recognise the different types ofusers so that the car park can function efficiently.

Simple parking design generally results in simple parkingmanagement and, at the same time, a higher degree of accept-ance of the parking facility by the driving public. This basicequation applies to the pre-design, design and post-designstages of any parking facility, regardless of whether it is a mul-ti-storey structure or a surface car park. The significance of thispractical equation is magnified in a commercial context; how-ever, its implications are equally important for any other type ofparking operation.

Designers should beware of falling into the trap of over-design, resulting in increased driver confusion and frustration aswell as unnecessary extra cost. On the other hand, oversimplifi-

PART 1

LOCATION OFVEHICULAR

ACCESS

PARKINGLAYOUT

PEDESTRIANCIRCULATION

SECURITY

INTERNALTRAFFIC

CIRCULATION

G.M. BURTONCONSULTING

PLANNINGCONSIDERATIONS

CAR PARKFEASIBILITY

COMMERCIALFEASIBILITY

PARKINGDEMAND

EXTERNAL FUNCTIONAL USERFRIENDLINESS

ARCHITECTURALSTRUCTURAL

ENVIRONMENTALAND

STATUTORY

AESTHETICS

CONTROL OFAIR POLLUTION(CAR EMISSION)

TRANSPORT ANDPARKING POLICY

RESTRAINT

BETTERUTILISATIONOF EXISTING

PARKING STOCK

STRUCTURE

PARKINGEQUIPMENT

SIGNAGE

JUNE 2009 • PARKING WORLD • www.parkingworld.com 17

cation without any real improvements to the design also shouldbe avoided.

An inefficient design could lead to a car park not being wellpatronised by users due to their preferences for more convenientalternatives, which, of course, might seriously affect the ultimatecommercial success of a development.

Planning User-Friendly Car ParksNowadays, planning user-friendly car parks is a different

ballgame from what it was only a few years ago. In fact, itrequires a considerable change in design approach. The times aregone when supply, regardless of quality, was the main concern.Today, car parks compete with one another, whether they arewithin an urban area or out of town. If drivers don’t like one carpark, they go into another one or they park somewhere else.

Car parks with associated hazards to safety – too manycolumns, tight layout with confusing and redundant traffic circu-lation patterns, bad or non-existent signage, etc. – do not attractdrivers at all.

External aesthetics significantly contribute to user-friend-liness (additional comments on this subject will be made fur-ther on).

All elements of car park design and operation must be of thehighest standard. Car parks should be not only pleasing to the eyebut also commercially viable; they should be safe, user-friendly,secure and incurring low maintenance costs.

The basic “ingredients” of user-friendliness are:Convenient, with efficient layouts and circulation patterns

without collision points and other surprises.Fast means of inter-floor and intra-floor travel, guiding traf-

fic to the nearest vacant parking spaces.Well-laid-out column grids allowing for best possible visi-

bility and safety. Preference is for clear span design in freestand-ing structures.

A high standard of illumination that will enhance confi-dence in safety and security.

A clean and bright interior and good-looking exterior.All in all, the planning of user-friendly car parks entails all

the considerations mentioned above, but first and foremost, itrequires the application of good design practice.

Part 2 of George Burton’s article will be found in the nextissue of Parking World, in which he will write about thespecifics of good design.

George M. Burton, M.I.E. (Aust), CEng, M.P.A. (Aust.), is Principalof Parking Design Specialists and Principal Consultant of ParkingConsultants International. He can be contacted at eithergmb@carparkingdesign.com orgeorge.burton@parkingconsultants.com.

This is not the case in the U.S., where the ‘quarter’ is still kingin parking meters. Unfortunately, it has proven to be a real problemfor some city treasuries whose hands have been tied in regards park-ing fee increases.

Let’s say the city bosses decide that they need more cash fromparking, and so double their current fees from $1 per hour to $2 perhour. This potentially doubles the number of coins going into themeter’s coin vault. Beauty! More cash flow.

Hang on, the meters now fill up twice as quickly and need to beemptied twice as often, otherwise they will jam and nobody pays.Extra staff are now required to empty the machines, count, sort andbank the cash.

The alternative? Invest large amounts of money that they prob-ably don’t have at this time in the economic cycle to purchase newmachines of some sort. Preferably ones that accept credit cards aswell as bank notes. That’s between a rock and a hard place.

Meanwhile, perhaps the U.S. Treasury could look at replacing the1 and 5 buck notes with coins? How about a $2 coin while they’re at it?

JP

Macquarie Bank and ParkingAustralia’s Macquarie Group is reportedly letting its parking

operations in the U.S. go back to its lenders. (See my April 27 Park-ing Today blog.) It also seems that Macquarie could be having prob-lems in Europe, too.

The parking business has dodged much of the problems with theeconomic downturn. However, those operations that focus on airportsand have a lot of debt could have some problems. My interview withPark ‘n Fly’s new president in May’s Parking Today noted that therehad been some downward pressure on the company’s occupancyrates, somewhere in the 10% to 15% range. Seems that if Macquarie

Between a Rock and a Hard PlaceI had the pleasure of a trip to the US late last year for work, LA

to be precise. It was my first trip overseas and was great fun.When I made my visit to the cash-exchange centre to buy some

U.S. dollars, I was immediately struck by the lack of differentiationin the ‘greenbacks’. Every denomination was virtually the same, thegreatest difference being the faces of the presidents gracing the front.And then my first purchase gave me some coin, and the largest onethey have is the world-renowned ‘quarter’.

Thinking on this now, it seems strange that a country that isalways seen as one moving ahead has done nothing to alter its cur-rency for ... I know not how long.

Here in Australia, we moved from pounds to dollars in 1966,with each denomination a different colour and size. Then a fewdecades later, we introduced plastic bank notes. These have provedextremely difficult to counterfeit – something the paper U.S. dollaralways seems to have problems with.

As inflation has worked its demon ways, the introduction of thedollar coin and then the two-dollar coin saw the removal of thosepesky little bank notes. And this simple move proved a great boon tomanufacturers and distributors of coin-operated machines, be theyfor confectionery, chips, cigarettes, drinks, etc.

It also meant that parking meters and ticket machines were giv-en a greater life span. They didn’t need bank note-recognition tech-nology as soon as might otherwise have been the case.

Editor Jolyon Porter and Publisher John Van Horn blogat the Parking World Web site, www.parkingworld.com.Log on and add your comments to his almost daily,well periodic but more than weekly, blogging. Here aresome samples.

PWBLOG

PW

Continued on Page 33

AUGUST 2010 • PARKING WORLD • www.parkingworld.com 5

Queuing Areas, Intake andDischarge Capacity

The efficiency of a car park’s design and its subsequent oper-ation is conditional on the provision of adequate entrance andexit capacities. They depend on the expected flow of traffic,extent of the queuing reservoir (particularly on entry), and theservice rate of the control equipment installed and on the streetabsorption capacity particularly at exit.

Levels of ServiceEach and every part of a car park can be assessed by its

dynamic performance, which is characterised by its dynamiccapacity, sometimes referred to as service capacity or handlingcapacity. These terms are applied to the maximum flow of cars(or people) which can be processed through the car park, or itspart under examination, in an hour. Analysis of car park dynamiccapacities is entailed in the level of service concept, which inprinciple is similar to the concept used in traffic engineering forroadway traffic.

N PART 2 OF HIS ARTICLE, GEORGEBurton goes more in depth on specific pointsof car park design. Here is a summary of thearticle. It contains initial paragraphs of allthe relevant topics that are discussed in detail

in the unabridged version which can be read onlinetogether with Part 1 at www.parkingworld.com.

SPECIFICS OF GOOD DESIGN PRACTICE

Car Park Location and Vehicular AccessUnless the car park provides free or subsidised parking, its

location is of utmost importance. An inconvenient location mayhave serious consequences on the commercial success of a carpark. The difference of one city block could mean a loss of com-mercial attraction and possible failure of the car park operation.

Generally speaking, the level of occupancy and revenues tobe derived from a car park are contingent upon its location, itsconvenience to the generator(s) it serves and to other centres ofattraction, the road network, and last but not least on the parkingconvenience in the facility itself.

BY GEORGE BURTON

Why Simple Design is Often ComplexPART 2

I

Continued on Page 11

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Internal Traffic CirculationIt is needless to say that employment of a simple and logi-

cal traffic circulation pattern, both interfloor and intrafloor, isan important consideration of good design practice. Whilstlarge shopping centre car parks, and particularly the onesentailing large surface parking areas, tend to allow for maxi-mum dispersion capability of users, the multi-level parkingfacilities must provide for delineated and highly disciplinedcirculation patterns.

Psychological FactorsNow some brief comments about a subject which does not

get a lot of exposure. When a driver enters a car park which hascolumns situated along the edges of the parking module (i.e. thecar park being a long span structure), the parking area appears tohim as being wider, more spacious and giving him a perceivedfreedom of movement. This type of column grid creates a posi-tive psychological effect on the driver and is therefore considereduser friendly.

On the other hand there are numerous factors of a psycho-logical nature which adversely affect drivers in car parking facili-ties and which can be avoided or mitigated, provided a little fore-sight is put into the process of functional design.

Car Park Signage and LinemarkingVertical signage and floor/pavement markings are an essen-

tial component in regulating parking and traffic activity in carparks. The significance of signage increases with the degree ofcomplexity of the car parking facility. Huge shopping centreparking areas would require more signage than smaller parkingfacilities where only very little signage would be required. How-

Why Simple Design is Often Complexfrom Page 5

ever, parking and traffic management cannot work efficientlywithout appropriate signs.

Aesthetics and Car Park UsefulnessAesthetics in the car parking planning is a consideration of

increasing significance, and simultaneously the subject of con-tinuous controversy. A point of concern is that environmentalrequirements are frequently onerous; the expectation of high lev-el of aesthetics may seriously affect the financial viability ofsome parking projects.

Car Parks for Special EventsThe principal difference of special event car parks is in the

rate of intake and discharge. Generally speaking these car parksexperience the almost simultaneous departure of all vehicles, andtherefore should be capable of filling and emptying in less thanone hour: the usual the time limit is 30 minutes or less.

ConclusionThe intention of this article was to discuss in a practical and

concise manner only some topics of functional design. However,these topics contribute to the degree of complexity of the processof planning and design of a user-friendly car park, which is sim-ple to understand, and simple to manage.

George M. Burton M.I.E. (Aust), CEng, M.P.A. (Aust.), M.P.C.C.(USA) is principal (retired) of Parking Design Specialists (former-ly GM Burton Consulting) and principal visiting consultant ofParking Consultants International. He can be contacted either ongmb@carparkingdesign.com orgeorge.burton@parkingconsultants.com

PW

11/01/11 1:44 PMParking World

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MagazineWhy Simple Design is Often ComplexPart 1

By George M. Burton

The intention of this two-part article is to describe the path a design process usually takes in order toarrive at a desirable product – a user-friendly car park – and to present an overview of somerelevant factors that influence the process of functional design of any parking facility.

The Car and the Parking Facility

As we all know, there is no such thing as free parking. Parking costs money and someone has to pay forit. In one way or another, it is the end user of the space who pays for parking, whether it is directly in thecar park, via a lease for the office/shop, or indeed in the prices of goods sold in the shops.

In this article, the term “commercial parking operation” relates to car parks where a fee is charged directlyto the user of the parking facility.

As illustrated in Exhibit 1, car park design is subject to numerous considerations, some of which affect thedesign process more than the others. Broadly speaking, car park design needs to take into account user,functional, environmental and other considerations.

User considerations are presented in the viability of a car parking development and, as such, are aprerequisite of the design process. Determination of the car park viability entails a Parking DemandAnalysis and a Commercial Feasibility Study.

Assuming that the parking demand analysis concludes there is a need for parking supply, then the resultsof the commercial feasibility study will determine whether the functional design process shall be instigatedor not.

Functional considerations are directly affected by the criteria of user friendliness and indirectly byenvironmental considerations.

However, environmental considerations directly relate to transportation, and therefore to parking as awhole, in their pursuit to improve air quality and to alleviate traffic congestion. The car, being an essentialutility, is a target of environmental concern.

The role of mass transportation is limited to areas of high population densities. It essentially moves peoplebetween two points. However, people depart from that and scatter in all directions.

Therefore, the car will remain an integral part of the transportation system and continue to be its primarymode.

Consequently, car parking is and will remain an essential part of all civic, cultural, social, business andshopping activities. People conducting these activities generate parking demand, which must beresponded to with sufficient, effective and efficient car parking facilities.

Simple Design = Simple Management

Car parks are the normal and natural termination points for access roads and city streets. However, theyare not the end of a journey. They act as an interchange where a person goes from being a motorist tobeing a pedestrian. Hence, car parks must be functional and meet the needs of both motorists andpedestrians. How efficiently the car park receives, stores and discharges cars determines its usefulness toits developer and the community it serves.

Simplicity and ease of parking are the basis of good functional design practice. The design must providefor traffic circulation and parking manoeuvres in a safe and expedient manner, with minimum delay andno hazard to the safety of vehicles and pedestrians. The design also must recognise the different types ofusers so that the car park can function efficiently.

Simple parking design generally results in simple parking management and, at the same time, a higherdegree of acceptance of the parking facility by the driving public. This basic equation applies to the pre-design, design and post-design stages of any parking facility, regardless of whether it is a multi-storeystructure or a surface car park. The significance of this practical equation is magnified in a commercialcontext; however, its implications are equally important for any other type of parking operation.

Designers should beware of falling into the trap of over-design, resulting in increased driver confusion andfrustration as well as unnecessary extra cost. On the other hand, oversimplification without any realimprovements to the design also should be avoided.

An inefficient design could lead to a car park not being well patronised by users due to their preferencesfor more convenient alternatives, which, of course, might seriously affect the ultimate commercial successof a development.

Planning User-Friendly Car Parks

Nowadays, planning user-friendly car parks is a different ballgame from what it was only a few years ago.In fact, it requires a considerable change in design approach. The times are gone when supply, regardlessof quality, was the main concern. Today, car parks compete with one another, whether they are within anurban area or out of town. If drivers don’t like one car park, they go into another one or they park

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somewhere else.

Car parks with associated hazards to safety – too many columns, tight layout with confusing andredundant traffic circulation patterns, bad or non-existent signage, etc. – do not attract drivers at all.

External aesthetics significantly contribute to user-friendliness (additional comments on this subject will bemade further on).

All elements of car park design and operation must be of the highest standard. Car parks should be notonly pleasing to the eye but also commercially viable; they should be safe, user-friendly, secure andincurring low maintenance costs.

The basic “ingredients” of user-friendliness are:

Convenient, with efficient layouts and circulation patterns without collision points and other surprises.

Fast means of inter-floor and intra-floor travel, guiding traffic to the nearest vacant parking spaces.

Well-laid-out column grids allowing for best possible visibility and safety. Preference is for clear spandesign in freestanding structures.

A high standard of illumination that will enhance confidence in safety and security.

A clean and bright interior and good-looking exterior.

All in all, the planning of user-friendly car parks entails all the considerations mentioned above, but firstand foremost, it requires the application of good design practice.

Part 2 of George Burton’s article will be found in the next issue of Parking World, in which he will writeabout the specifics of good design.

George M. Burton, M.I.E. (Aust), CEng, M.P.A. (Aust.), is Principal of Parking Design Specialists andPrincipal Consultant of Parking Consultants International. He can be contacted at eithergmb@carparkingdesign.com or george.burton@parkingconsultants.com.

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WHY SIMPLE DESIGN IS OFTEN COMPLEX –Part 2By George Burton M.I.E. (Aust)

SPECIFICS OF GOOD DESIGN PRACTICE

Car Park Location and Vehicular Access.

Unless the car park provides free or subsidised parking, itslocation is of utmost importance. An inconvenient locationmay have serious consequences on the commercial successof a car park. The difference of one city block could mean aloss of commercial attraction and possible failure of the carpark operation.

Generally speaking, the level of occupancy and revenues tobe derived from a car park are contingent upon its location, itsconvenience to the generator(s) it serves and to other centresof attraction, the road network, and last but not least on the

parking convenience in the facility itself.

A car park should be located within walking distance of the main places of destination. (A point toremember is the fact that people are prepared to walk longer distances when they park free of charge.) Ifpossible it should not be tucked away out of sight or its entrance located in secondary streets. This is quitea contentious issue in large cities where a primary location may not be possible due to various reasons,e.g. traffic implications on street network, urban planning requirements, pedestrianization of Frontal Street,etc. If the car park entrance is to be located away out of sight, then access to it should be clearly signedand the car park occupancy advised on route (by dynamic parking guidance signs) so that redundanttraffic circulation within the street system can be minimized and, if necessary, alternative car parksdirected to.

However, in small cities or suburban shopping districts, where the knowledge of parking areas is moreprevalent, car park entrances may be located in secondary streets.

As mentioned above, car park entrances should be clearly defined and obviously distinguishable fromexits. Increased attention should be paid to the architectural design of entrances as the pleasing andinviting “first impression” can contribute to successful parking operation.

The number of entries and exits should be restricted to what is actually required. Broadly speaking, thenumber of entry and exit lanes is determined by the maximum number of vehicles that can be processedthrough a lane in one hour. Providing more than the required number of accessways may not necessarilyalleviate traffic problems and could, on the contrary, create operational difficulties and security problemsinside the car park.

Where possible, both entries and exits should be orientated to favour left-hand turns for incoming andoutgoing traffic. Vehicular access to the site should be planned so as:

to provide easy access to parking by means of a satisfactory rate of receiving, storing and dischargingvehicles,

to minimize conflicts between vehicles and pedestrians,

to minimize the impact of driveways and ramps on the building frontage, and

to diffuse traffic onto surrounding streets in a satisfactory manner.

Queuing Areas, Intake and Discharge Capacity

The efficiency of a car park’s design and its subsequent operation is conditional on the provision ofadequate entrance and exit capacities. They depend on the expected flow of traffic, extent of the queuingreservoir (particularly on entry), and the service rate of the control equipment installed and on the streetabsorption capacity particularly at exit.

Sufficient queuing capacity should be provided at entry between vehicular control points and the streetalignments so that cars can queue inside the site and not adversely affect traffic flow in surroundingstreets or obstruct movements in other parts of the car park.

Good design practice would also call for the provision of a queue length on exiting, between the exitcontrol points and street alignment. This would not only accommodate cars waiting to enter the road flowbut it also enable a driver to draw clear immediately when the boom gate opens. It would also alleviatecars from stacking up and hampering the check-out procedures in case pedestrians are crossing thedriveway.

The length of queuing/holding reservoir on exiting can be determined on the basis of traffic engineeringanalysis of a car park exit onto a road as for a T-junction.

Ideally car parks should be capable of receiving and discharging their static capacity within a maximum ofone hour. However, we don’t live in an “ideal “world and this desired aim is frequently impossible toachieve. Consequently car parks are usually designed to receive and discharge the projected peak inflowsand outflows (determined by traffic impact studies and usually expressed as a % of the static capacity)within one hour.

The term static capacity relates to the total number of parking spaces in a car park. Special event carparks, i.e. the ones that cater to a surge type of parking demand should be able to empty in less than onehour. It is not unusual for the discharge capacity of such facilities to be 30 minutes.

Levels of Service

Each and every part of a car park can be assessed by its dynamic performance, which is characterised by

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its dynamic capacity, sometimes referred to as service capacity or handling capacity. These terms areapplied to the maximum flow of cars (or people) which can be processed through the car park, or its partunder examination, in an hour. Analysis of car park dynamic capacities is entailed in the level of serviceconcept, which in principle is similar to the concept used in traffic engineering for roadway traffic.

Level of service is defined as a qualitative measure describing operational conditions within a trafficstream, and their perception by motorists and passengers [1]. For example, the parking space dimensionsrecommended in some countries are based on a level of service range “C” to “D” which is consideredadequate for low turnover operations. Other parking consultants using the same concept of dynamicperformance define the levels of service for car parking facilities thus:

High Level of Service ……when the traffic flows are below the dynamic capacity;

Satisfactory Level of Service ……when the traffic flows are equal to the dynamic capacity;

Unsatisfactory Level of Service ……when the traffic flows are in excess of the dynamic capacity.

It is obvious that the establishment of dynamic capacities is of paramount significance in the level ofservice concept.

Dynamic capacities of aisles and parking areas can be expressed by a number of formulas as applicablefor inbound and outbound flows. They are subject to numerous variables such as aisle width, spacedimensions, % of cars reversing into spaces, etc. A good example is presented in Exhibit 2 depicting thefloor plan of an underground multi-level car park for 2500 cars with which the author was involved someyears ago. Dynamic capacity of the principal circulation aisle was calculated as 1100 cars inbound and900 cars outbound. In order to accommodate the projected peak traffic flow (particularly on the levelsnearest to the entry and exit control points) there were two circuits of express vertical travel employedcatering to both the inbound and outbound traffic. Adoption of this measure resulted in achieving a highlevel of service inside the car park.

An interesting application of dynamic capacity is for entries and exits. Car park entrances and exits, whichincorporate boom gate control, behave asintersections with traffic signals allowing onevehicle through each green cycle. In thestandard procedures of traffic engineering forcapacity analysis, the rate of traffic flow ismeasured in 15 min periods, although aperiod of 30 minutes or the full period of onehour is often used. In the car parkingapplication the peak 15 min rate of flow isthen expressed as the peak hourly flowequivalent and as such is used forascertaining dynamic capacity of individualentrances and exits or the internal circulationsystem in the car park.

For example, a peak flow of 680 cars / hourhas a peak hourly flow equivalent of say 800cars / hour. In practical terms this means thattwo automatically controlled entry lanes, eachhaving a service rate of say 400 cars / hour, would provide a satisfactory level of service during the peak15 minutes and a high level of service outside this period.

Queue length on entry is another dynamic characteristic, which must be established in order to ensure thatcars would queue inside the car park and not on the street. Queues that would occur are derived from anapplication of the queuing theory, which is based on rather complicated equations of Poisson distributionof the volume of arriving vehicles for single and particularly multi-channel queue requirements.

Internal Traffic Circulation

It is needless to say that employment of a simple and logical traffic circulation pattern, both interfloor andintrafloor, is an important consideration of good design practice. Whilst large shopping centre car parks,and particularly the ones entailing large surface parking areas, tend to allow for maximum dispersioncapability of users, the multi-level parking facilities must provide for delineated and highly disciplinedcirculation patterns.

Various types of patronage could dictate the pattern of internal traffic circulation in multi-storey car parks.In high turnover car parks, a one-way flow system would be preferable, whereas in commuter car parkswith significant peak ingress in the morning and peak egress in the evening, consideration could be givento two-way traffic circulation. The latter usually results in a more economically attractive structure.

However, in multi-level car parks the basic recommendation would be for one-way traffic circulation with arepetitive floor pattern. Two-way internal traffic circulation may cause congestion of tidal traffic, creatingnumerous collision points in general and on the interacting 2-way aisles in particular and slowing down theflow of traffic.

The following comments concern a recurring question as to the use of clockwise or anti-clockwisecirculation pattern in car parks and are prompted by the author’s involvement several years ago inarbitration between a local government authority and a developer. The authority insisted on usingclockwise traffic circulation wherever possible.

As we all know, circulation on a ramp system may be clockwise or anticlockwise. Clockwise rotation isgenerally preferred because it places drivers inside of turns, enabling better vehicle handling. This isparticularly relevant and even amplified if ramp dimensions and related turning radii are at their minimum.It is important to note however, that this is first of all beneficial to the very means of interfloor travel, i.e. tothe clearway ramp systems that are in fact relatively steep and narrow roadways and therefore have moreprominent safety hazards than the level floors.

Ramp systems usually dictate the pattern of intrafloor (i.e. horizontal) traffic circulation in commonly sizedmulti-level car parks containing up to say three parking modules and a repetitive floor pattern. Such rampsystems would often take up a significant proportion of the parking floor. A typical example is a split-levelcar park where the clockwise circulation is indeed advantageous.

However, this advantage may be inhibited in car parks with large floor areas, containing a multi-aisle layoutand accommodating hundreds of cars per floor. In these cases, it is the parking layout that usually dictatesorientation of the intrafloor traffic circulation, which are then suitably complemented by the ramp system. Itis quite common for large parking areas to adopt unidirectional flow along the floor perimeter aisles andtwo-way traffic in cross aisles with the clockwise traffic circulation having no clear advantage overanticlockwise. In fact, the use of anticlockwise traffic circulation along perimeter aisles may significantlyreduce if not eliminate the crossing interactions of traffic streams between the perimeter aisle and crossaisles.

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Psychological Factors

Now some brief comments about a subject which does not get a lot of exposure. When a driver enters acar park which has columns situated along the edges of the parking module (i.e. the car park being a longspan structure), the parking area appears to him as being wider, more spacious and giving him aperceived freedom of movement. This type of column grid creates a positive psychological effect on thedriver and is therefore considered user friendly.

On the other hand there are numerous factors of a psychological nature which adversely affect drivers incar parking facilities and which can be avoided or mitigated, provided a little foresight is put into theprocess of functional design.

Although psychological factors may be difficult to quantify, they can be broadly qualified as:

Tunnel effect - in long and narrow enclosed corridors, drivers feel anxious and claustrophobic after ashort period of time. People tend to object driving in tunnels. Typical examples are long straight or circularramps, enclosed with solid walls on both sides.

Ramp structures should be as open as practicable, with abundant illumination (avoiding glare which canblind drivers) and with adequate sight distances.

Bridge effect - when driving in long, narrow suspended corridors. Drivers feel uncertain on narrow bridgessuspended in open space; their awareness of height is accentuated and their driving concentrationdistracted.

Note: Parapet walls along long ramp sides are often used to reduce drivers’ distraction by the emptinessoutside the ramp structure.

Spiral effect – when too many revolutions take place over a relatively small area. Notes:

(a) There is consensus of opinion that about six revolutions is the preferred maximum for a circular ramp.

(b) It is agreed that the car park’s vertical circulation pattern should be limited to six revolutions (i.e.maximum six floor circuits on the way up or down).

Column effect – when too many columns are employed within a car park, thus creating an impression ofvisual pollution, smallness and tightness of the space with increased hazard to safety or even personalsecurity, increased difficulty of manoeuvring, etc. Drivers may feel that the space is closing in on them.

Roller-coaster effect – when there is no continuity of gradient maintained on ramps or ramped floors. Thiseffect is amplified on the ramps linking floors with a highly repetitive floor pattern.

Car Park Signage and Linemarking

Vertical signage and floor/pavement markings are an essential component in regulating parking and trafficactivity in car parks. The significance of signage increases with the degree of complexity of the car parkingfacility. Huge shopping centre parking areas would require more signage than smaller parking facilitieswhere only very little signage would be required. However, parking and traffic management cannot workefficiently without appropriate signs.

Signage has gone through considerable technological and qualitative improvement in recent years.Continuously increasing environmental and energy saving consciousness has brought about intensifiedapplication of dynamic guidance systems which are now being frequently used inside and outside carparking facilities. Application of dynamic signs can reduce the extent of travel and eliminate redundanttraffic circulation, thus saving on travel time, reducing fuel consumption and at the same time decreasingair pollution.

External route guidance sign systems are becoming an essential part of street networks and they shouldplay an even more significant role in the future. In relation to car parking such route guidance systemsguide motorists to the car park situated near or at their place of destination.

External signs are of great importance, especially for public car parks. Viability and usefulness of publiccar parks can largely depend upon external signs identifying the facility with enough impact to catch theattention of those who are unfamiliar with the car park.

As noted earlier, every car park can be described by its static and dynamic characteristics. Similarly thecar park signs can be described as,-

Static signs – i.e. painted (silk screened, laminated, etc.) or illuminated, imparting basic information for thedrivers in terms of regulation and warning.

Dynamic signs – which automatically guide drivers to available parking spaces.

The principle of a dynamic sign system is in the inductive loop coils detectors embedded in the floor oroverhead ceiling mounted ultra-sonic directional sensors. Ultrasonic sensors are gradually replacinginductive loops due to their extremely accurate directional vehicle counts including identification of nonvehicles such as shopping trolleys and pedestrians and additional important positive features. They countcars in and out of the specific areas and relay this information to counters [or a central processing unit(CPU)] which have been preset with the capacity of a particular area. The counters (or the CPU) would, inturn, activate the relevant dynamic sign.

Aesthetics and Car Park Usefulness

Aesthetics in the car parking planning is a consideration of increasing significance, and simultaneously thesubject of continuous controversy. A point of concern is that environmental requirements are frequentlyonerous; the expectation of high level of aesthetics may seriously affect the financial viability of someparking projects.

Many architects do not realise that the quality of functional design is more important to the customer thanan aesthetically pleasing façade. After all car parks are constructed for parking cars in them and thatexternal presentation cannot compensate for an internal design which is not user friendly.

Therefore it is really up to the combined efforts of architects and parking consultants to sensibly addressthe whole issue of aesthetics without interfering with the car park’s usefulness. We are all interested insafeguarding environmental and aesthetical considerations and understand that car parks must be userfriendly, appealing and inviting. An efficiently functional, bright and clean interior is as important as a good-looking exterior.

Car Parks for Special Events

The principal difference of special event car parks is in the rate of intake and discharge. Generallyspeaking these car parks experience the almost simultaneous departure of all vehicles, and therefore

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should be capable of filling and emptying in less than one hour: the usual the time limit is 30 minutes orless. For example, if a car park with a 1000 space capacity were to empty within 30 minutes, then its peakhour equivalent would be 2000 cars / hour and the whole car park design must take this requirement intoaccount. In other words the design must provide for dynamic capacity of 2000 cars / hour to enable thecar park to discharge its static capacity of 1000 cars within 30 minutes.

Special event parking requires a lot of preparation even though the use of sophisticated access andrevenue control equipment in conjunction with dynamic parking guidance systems can go a long way inassisting the overall operation.

During the course of the event managerial resources must be properly coordinated and prepared to dealwith the unexpected and also with special parking arrangements.

It is needless to say that correct functional design goes hand-in-hand with effective and efficientmanagement of special event parking.

One of the most important special event car parks is the Sydney Olympic Park P1 car parking facility for3400 cars on 6 elevated + 1 basement levels, built prior to Sydney Olympic Games in 2000. An overviewof the design process of this car park can be found in the Parking (Australia) magazine issue No. 3, 1999,[7].

Conclusion

The intention of this article was to discuss in a practical and concise manner only some topics of functionaldesign. However, these topics contribute to the degree of complexity of the process of planning anddesign of a user-friendly car park, which is simple to understand, and simple to manage.

The paper endeavours to combine some theory with practical implications, thanks to the writer being ableto wear two hats, one of a parking consultant/traffic engineer and the other one of a practical car parkingoperator.

Due to the limited scope and objectives of this paper, additional aspects of functional parking design, suchas: pedestrian circulation and pedestrian signage, security and safety, parking equipment andtechnological trends, construction trends, etc have been omitted.

George M. Burton M.I.E. (Aust), CEng, M.P.A. (Aust.), M.P.C.C. (USA) is principal of Parking DesignSpecialists (formerly GM Burton Consulting) and principal consultant of Parking Consultants International.He can be contacted either on gmb@carparkingdesign.com or George.burton@parkingconsultants.com

Bibliography References

[1] Guide to Traffic Engineering Practice, Part 2, Roadway Capacity, NAASRA, 1988

[2] Guide to Traffic Engineering Practice, Part 1, Traffic Flow, NAASRA, 1988.

[3] AS 2890.1 – 2004, Part 1, Car Parking Facilities,

[4] The Dimension of Parking 3rd (draft) edition and 4th edition, ULI & NPA, 1992 & 2001.

[5] M.S. Smith: The Analytical Approach to Entry/Exit Design, Parking (US), May-June 1988.

[6] R.A. Weant: Parking Garage Planning and Operation, ENO Foundation for Transportation, 1978.

[7] G.M. Burton: Sydney Olympic Park P1 Car Parking Facility, Parking (Aust.) Issue #3/99.

[8] G.M. Burton: Handbook on Parking Information, Kings Parking Company, 1973

[9] P.B. Ellson: Dynamic Capacities of Car Parks, RRL Report LR 221.

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