bfc3082 chapter 4b

8/7/2019 BFC3082 Chapter 4b

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THE IMPACTS OF PARKING

Availability, Convenience and Cost of Parking affects mode choiceAvailability, Convenience and Cost of Parking affects mode choice

BFC3082 Traffic and Road Safety Engineering

PARKINGPARKING

An owner of a private automobile is likely to use their automobileto access their destination if:

Parking is plentifulParking is conveniently located

Cost of parking is reasonable

An owner of a private automobile is NOT likely to use their

automobile, and choose to use alternative modes if:Parking is scarce (hard to obtain)

Parking is inconvenient

Cost of parking is expensive



PARKING POLICIESPARKING POLICIES

To strike a compromise between the amount of curb space devoted toTo strike a compromise between the amount of curb space devoted toparking, and for moving vehicles.parking, and for moving vehicles.

To make provision for parking of delivery vehicles, short term parkersTo make provision for parking of delivery vehicles, short term parkersand long term parkers.and long term parkers.

To design parking lots and their approaches so that street traffic isTo design parking lots and their approaches so that street traffic isnot adversely affected by the ingress and egress of parkers.not adversely affected by the ingress and egress of parkers.





To ensure that the interests of business establishments along theTo ensure that the interests of business establishments along thestreet is enhanced by good parking arrangements.street is enhanced by good parking arrangements.

To ensure that parking policies and public transport policies areTo ensure that parking policies and public transport policies arecomplementary; for example, car parks adjacent to bus stations andcomplementary; for example, car parks adjacent to bus stations androutes would enhance bus ridership.routes would enhance bus ridership.





To preserve the character of the neighborhood by restricting parkingTo preserve the character of the neighborhood by restricting parkingand enforcing landand enforcing land- -use control.use control.

To control parking supply and demand through pricing mechanism;To control parking supply and demand through pricing mechanism;encourage short term parking, and discourage long term parking mayencourage short term parking, and discourage long term parking mayserve to enhance the CBD.serve to enhance the CBD.





TYPES OF PARKINGTYPES OF PARKING

PUBLIC PARKINGPUBLIC PARKINGOnOn--street parking may be free or not, and it may be regulated orstreet parking may be free or not, and it may be regulated orunregulated (e.g. No Parking During Rush Hours, No Overnightunregulated (e.g. No Parking During Rush Hours, No OvernightParking).Parking).

OffOff--street parking is usually in parking lots, decks (with multistreet parking is usually in parking lots, decks (with multi- -

purpose buildings), or in exclusive parking structures.purpose buildings), or in exclusive parking structures.




TYPES OF PARKINGTYPES OF PARKING

PRIVATE PARKINGPRIVATE PARKINGUsually offUsually off--street, private parking includes home or apartmentstreet, private parking includes home or apartmentbuilding garages, stalls, driveways, or affiliatebuilding garages, stalls, driveways, or affiliate- -specific parkingspecific parking(permit required).(permit required).

For owners of homes and apartments or businesses, and exclusive forFor owners of homes and apartments or businesses, and exclusive for

members of clubs.members of clubs.OnOn--street private parking also can exist.street private parking also can exist.




ONON--STREET PARKING (CURB PARKING)STREET PARKING (CURB PARKING)

ANGLE PARKINGANGLE PARKING

Angled parking allows more spaces perAngled parking allows more spaces perlinear length of curb.linear length of curb.

Maneuver for angle parking is easierManeuver for angle parking is easiercompared to parallel parking.compared to parallel parking.

However, it restricts traffic movementHowever, it restricts traffic movement

on streets more than parallel parking.on streets more than parallel parking.

PARALLEL PARKINGPARALLEL PARKINGTandem parallel parking is recommendedTandem parallel parking is recommendedfor major streets with heavy vehicles.for major streets with heavy vehicles.

Also recommended for roadways whichAlso recommended for roadways whichare not wide.are not wide.

Time taken to parallel park is longer andTime taken to parallel park is longer andmay also encourage double parking andmay also encourage double parking andwaiting.waiting.



L ecturer: Mr. Basil David Daniel

ONON--STREET PARKING (CURB PARKING)STREET PARKING (CURB PARKING)

Curb Parking Geometry DesignCurb Parking Geometry Design




OFFOFF- -STREET PARKINGSTREET PARKING

SURFACE PARKING LOTSSURFACE PARKING LOTS

BASEMENT CAR PARKSBASEMENT CAR PARKS





MULTISTOREY CARPARKSMULTISTOREY CARPARKS





MECHANICAL CAR PARKSMECHANICAL CAR PARKS





MultiMulti--storey Parking Geometry Designstorey Parking Geometry Design



PARKING STUDIESPARKING STUDIES

Parking studies are done in order to:Parking studies are done in order to:

-- estimate parking demand.estimate parking demand.

-- analyse the capacity and use of parking facilities.analyse the capacity and use of parking facilities.

Parking studies includeParking studies include financial feasibilityfinancial feasibility ,, functional designfunctional design ,,structural designstructural design andand demand studiesdemand studies ..

TYPES OF PARKING DEMAND STUDIESTYPES OF PARKING DEMAND STUDIES

-- ComprehensiveComprehensive

-- LimitedLimited-- Site SpecificSite Specific

Sampling must be done carefully in order to prevent bias towardSampling must be done carefully in order to prevent bias towardoversampling of shorterm parkers.oversampling of shorterm parkers.





METHODS OF COLLECTING PARKING DATAMETHODS OF COLLECTING PARKING DATA

Ins and OutsIns and Outs

All vehicles parked in the focus area are counted at the beginning ofAll vehicles parked in the focus area are counted at the beginning ofthe survey period.the survey period.

Then the vehicles entering and exiting the area are counted.Then the vehicles entering and exiting the area are counted.

This method can yield the overall accumulation and occupancy only.This method can yield the overall accumulation and occupancy only.

Fixed PeriodFixed Period

All vehicles parked in the focus area are counted at the beginning ofAll vehicles parked in the focus area are counted at the beginning ofthe survey period.the survey period.

Occupancy counts are conducted every 15 minutes to 1 hour.Occupancy counts are conducted every 15 minutes to 1 hour.This method may miss short term parkers and may be difficult forThis method may miss short term parkers and may be difficult forprivate garages.private garages.





METHODS OF COLLECTING PARKING DATAMETHODS OF COLLECTING PARKING DATA

License Plate SurveyLicense Plate Survey

Most accurate and realistic data because every parking space isMost accurate and realistic data because every parking space ismonitored at fixed intervals.monitored at fixed intervals.

This method is very labor intensive and it entails certain liabilityThis method is very labor intensive and it entails certain liability

problems.problems.This can be done by partly omitting the first or last digit of theThis can be done by partly omitting the first or last digit of thelicense plate.license plate.

OTHER PARKING STUDY METHODSOTHER PARKING STUDY METHODS

PhotographsPhotographsParking Meter RevenueParking Meter Revenue

Attendant ReceiptsAttendant Receipts




Sample of License Plate SurveySample of License Plate Survey

* The numbers represent the first time that a vehicle parked in the space.

* The check marks indicate that the same vehicle was in the space on the next circulation.

* The E suffix indicates that the meter was expired.

* The T prefix indicates that a delivery truck was using the parking space. If this occurs frequently, there may be a need for a truck

loading zone.




Parking DurationParking Durationis the average length of time that a vehicle is parked.is the average length of time that a vehicle is parked.

Parking duration =Parking duration = Number of Observations x IntervalNumber of Observations x IntervalNumber of VehiclesNumber of Vehicles

Example calculation (based on sample on slide 9)Example calculation (based on sample on slide 9)

Parking duration for space 109:Parking duration for space 109:


DurationDuration 109109 == 8 x 158 x 15 = 24.0 mins / veh= 24.0 mins / veh

55



Parking TurnoverParking Turnoveris the number of different vehicles parked in the study periodis the number of different vehicles parked in the study period

Parking turnover =Parking turnover = Number of Different Parked VehiclesNumber of Different Parked VehiclesNumber of Parking SpacesNumber of Parking Spaces

Example calculation (based on sample on slide 9)Example calculation (based on sample on slide 9)

Parking turnover for spaces 109 to 112 over a 2.5 hour period:Parking turnover for spaces 109 to 112 over a 2.5 hour period:


TurnoverTurnover 109109--112112 = 12/4 = 3.0 veh / space= 12/4 = 3.0 veh / space



EXAMPLE:EXAMPLE:

An office has the following characteristics:

Hours of operation: 6 A.M. to 8 P.M (14 hours)

Number of parking spaces in the garage: 500

80% are commuters with average parking duration of 8 hours

10% are visitors parking for an average of 2 hoursThe remaining are shoppers parking for an average of 3 hours

However observations made at the garage indicate that 15% of

visitors during peak hours (10 A.M. to 12 P.M. and 1 A.M. to 3P.M.) do not find parking.

How many additional spaces should be added to the garage to meetthe demand?




SolutionSolution

Space hours demanded:

Commuters: 80% x 500 x 8 =3200Visitors: 10% x 500 x 2 =100Shoppers: 10% x 500 x 3 = 150

Demand not served: 15% x 500 x 4 = 300

Total space-hours demanded = 3750

Total space-hours served = 3450

Balance space-hours = 300

Because the additional demand is during 4 hours;

The number of additional spaces needed is 300/4 = 75 spaces.

Discussion:Discussion:Although 75 additional spaces are needed only during the 4 peak hours, it isopen debate whether the garage owner should spend money to meet thisdemand, because for the rest of the operating time (14 ² 4 = 10 hrs), it is

likely that the 75 spaces may not be occupied




ANALYSIS of PARKING FACILITIESANALYSIS of PARKING FACILITIES

ADEQUACY ANALYSIS


The adequacy of a parking facility can be measured by calculating theprobability that an entering vehicle may not find a parking space.

A high probability of rejection (not able to find a space) may indicatethat an expansion of the parking facility is warranted.

The probability of rejection can be calculated by comparing thetraffic load to the number of parking bays, as shown below:

A = Q x T

where A = traffic load (veh)Q = incoming vehicle flow rate (veh/hr)T = average parking duration (hr)



ADEQUACY ANALYSIS


Next, calculate the probability of rejection using the formula:

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ª

¨

¹¹º

¸©©ª

¨

!

!...

!!!

!

where = probability of rejection= traffic load= number of parking bays

If the probability of rejection is high, you may want to consideradding more parking bays in the facility.



Example:


A parking facility that has 50 parking bays receives an incomingvehicle flow rate of 120 vehicles per hour. If the average parkingduration is 50 minutes, analyse the adequacy of this parking facility.

Solution:

Q = 120 veh/hrT = 50 mins = 5/6 hrs

A = Q x T = 120 x 5/6 = 100 veh

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¨

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!...

!!!

!

¡

¢

£ ¤

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= . 9

.9% of the incoming vehicles will not find a parking space.This parking facility is NOT ADEQUATE.



Exercise:


It was observed during an 8-hour study that 96 vehicles enter theparking lot of a local electronics store. The parking lot has only 5parking spaces. Customers park their cars for an average of 15minutes. Calculate the probability that an incoming vehicle will notfind a parking space.



DEFINITIONS


Parking durationParking duration : the actual length of time a vehicle remains in one: the actual length of time a vehicle remains in oneparking space.parking space.

Parking accumulationParking accumulation : the total number of vehicle parked in a specific: the total number of vehicle parked in a specificarea at a specific time.area at a specific time.

Parking loadParking load : the area under the accumulation curve between two specific: the area under the accumulation curve between two specifictimes.times.

Parking spaceParking space : an area large enough to accommodate one vehicle with: an area large enough to accommodate one vehicle withrestricted access (no blockage by another parked vehicle), but excludingrestricted access (no blockage by another parked vehicle), but excludingmaneuver space.maneuver space.

Parking demandParking demand : the number of vehicles whose drivers desire to park at: the number of vehicles whose drivers desire to park ata specific location or in a general area. It is usually expressed as thea specific location or in a general area. It is usually expressed as the

number of vehicles during the peak parking hour.number of vehicles during the peak parking hour.Parking supplyParking supply : the number of parking spaces available for use.: the number of parking spaces available for use.

Parking turnoverParking turnover : number of vehicle utilizing the same stall over a given: number of vehicle utilizing the same stall over a givenperiod of time (four or more during an 8period of time (four or more during an 8- -hour period indicates a highhour period indicates a high

turnover rate). Parking turnover measures utilization.turnover rate). Parking turnover measures utilization.



DEFINITIONS


W alking distanceW alking distance : the actual distance traveled by foot from the: the actual distance traveled by foot from theparking facility to the parker·s trip destination.parking facility to the parker·s trip destination.

Parking deficiencyParking deficiency : the extent to which parking demand exceeds: the extent to which parking demand exceedssupply, expressed in number of parking spaces.supply, expressed in number of parking spaces.

Average durationAverage duration= total vehicle hours= total vehicle hours

--------------------------------------------------------total number of vehicles that parkedtotal number of vehicles that parked

Occupancy (%)Occupancy (%) = 100 x number of spaces occupied= 100 x number of spaces occupied

------------------------------------------------------------------Total spaces availableTotal spaces available

bfc3082 chapter 4b

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