# ITE Journal April 2018 - 41

```Table 1. Shared Parking Calculation for 200K Square Feet of Office/10K Square Feet of Retails Mix.
Building
Use

Size

Peak Parking
(individ. peaks)

Weekday AM
(10-11 am)

Weekday Lunch
(12-2 pm)

Weekday PM
(3-4 pm)

Weekday
Evening (7-8pm)

Saturd Midday
(12-2 pm)

1000 SF

Ratio

Spaces

% Present

Cars

% Present

Cars

% Present

Cars

% Present

Cars

% Present

Cars

Office

200

3

600

100%

600

85%

510

90%

540

10%

60

20%

120

Retail

10

5

50

70%

35

85%

43

75%

38

70%

35

100%

Total

650

635

553

578

95

50
170

Peak Parking Demand: 635
Shared Parking Savings: 15

2%

Table 2. Shared Parking Calculation for 200K Square Feet of Office/100K Square Feet of Retails Mix.
Building
Use

Size

Peak Parking
(individ. peaks)

1000 SF

Weekday AM
(10-11 am)

Weekday Lunch
(12-2 pm)

Weekday PM
(3-4 pm)

Weekday
Evening (7-8pm)

Saturd Midday
(12-2 pm)

% Present

Cars

% Present

Cars

% Present

% Present

Ratio

Spaces

% Present

Cars

Cars

Cars

Office

200

3

600

100%

600

85%

510

90%

540

10%

60

20%

120

Retail

10

3

500

70%

350

85%

425

75%

375

70%

350

100%

500

Total

1,100

950

935

915

410

620

Peak Parking Demand: 950
Shared Parking Savings: 150

14%

on the empirical data published in Parking Generation and other
sources, or they could be based on specific occupancy surveys.
The first example in Table 1 has 200,000 square feet (SF) of office
space and 10,000 SF of retail space, and shows a savings of 2 percent
of the required spaces. The second example in Table 2, with 100,000
SF of retail, shows a savings of 14 percent of required parking.
As shown by the examples in Table 1 and Table 2, the savings
from shared parking can vary substantially. They depend on
the types of uses sharing the same parking facility and on the
magnitude of each use. Generally, the more uses in a development,
the greater the shared parking benefits.

How Can Shared Parking be Regulated?
On one hand, there is a desire to codify the benefits of shared
parking in a simple manner; on the other hand there is a reality
that the benefits can vary substantially depending on the uses
and their magnitude. It does not appear that one can simply
set a fixed percentage credit if two or more uses share the same
parking facility, since the benefits vary so substantially. The zoning
requirement should refer to a shared-parking analysis prepared
by a qualified professional estimating the parking demand of
each use by time period. This analysis shall identify the critical
time period with the highest total parking demand representing
the number of shared parking spaces to be supplied. The time
periods analyzed need to include all periods that could represent

high parking demands. They typically include weekday mornings,
lunch time, weekday evenings, night time, and Saturday middays.
However, depending on the uses, other periods may need to be
analyzed as well.
The parking ratio given by zoning would typically be used for
the base calculation. The acceptance of shared parking analyses
may be subject to approval by a planning board or a municipality's
professionals. The applicant needs to make sure that reasonable
percentages of presence are used for each time period. These can
be based on ITE Parking Generation data, or the municipality can
request a survey of local occupancy data by hour. Often there are
only a limited number of data points that are critical. For instance,
in the Table 2 example with 200,000 SF of office space and 100,000
SF of retail use, the only new factors critical for the determination
are the percentages of presence for the retail uses in the morning
period, lunch time, and afternoon period.
The question is often raised: what happens if one of the uses in
the shared parking mix changes? Like any other use change subject
to different zoning requirements, the applicant needs to analyze
the effects of the change on the shared-parking calculation. New
parking occupancy surveys may be helpful in determining the
real parking demand, as opposed to the demand estimated based
on zoning. These changes can often be accommodated within the
overall parking supply, since the zoning ratios are often based on
worst-case assumptions.
w w w .i t e.or g

Apri l 2 01 8

41

```
http://www.ite.org

President’s Message
Director’s Message
People in the Profession
ITE News
Technical Programs Division Spotlight
Ethics Column: Responsible Engineer
Member to Member: Sammy Xiaoming Chen, Ph.D., P.E., PTOE, PTP
Where in the World?
Calendar
Industry News
New Products
Love My Hood: Kitchener’s Resident-Led Traffic Calming Program Advances Safety and Placemaking
Placemaking through a Traffic Signal Box Art Project: Effect of Artist Wrap to Cabinet Temperature
Shared Parking: Effective and Simple
Relationship between Geometric Elements and Wrong-Way Crashes at Partial Cloverleaf Interchange Terminals
Professional Services Directory
ITE Journal April 2018 - 1
ITE Journal April 2018 - 2
ITE Journal April 2018 - 3
ITE Journal April 2018 - President’s Message
ITE Journal April 2018 - 5
ITE Journal April 2018 - Director’s Message
ITE Journal April 2018 - 7
ITE Journal April 2018 - People in the Profession
ITE Journal April 2018 - 9
ITE Journal April 2018 - 10
ITE Journal April 2018 - 11
ITE Journal April 2018 - ITE News
ITE Journal April 2018 - 13
ITE Journal April 2018 - Technical Programs Division Spotlight
ITE Journal April 2018 - 15
ITE Journal April 2018 - Get Ready for Minneapolis!
ITE Journal April 2018 - 17
ITE Journal April 2018 - Ethics Column: Responsible Engineer
ITE Journal April 2018 - 19
ITE Journal April 2018 - 20
ITE Journal April 2018 - Member to Member: Sammy Xiaoming Chen, Ph.D., P.E., PTOE, PTP
ITE Journal April 2018 - 22
ITE Journal April 2018 - Calendar
ITE Journal April 2018 - New Products
ITE Journal April 2018 - 25
ITE Journal April 2018 - 26
ITE Journal April 2018 - Love My Hood: Kitchener’s Resident-Led Traffic Calming Program Advances Safety and Placemaking
ITE Journal April 2018 - 28
ITE Journal April 2018 - 29
ITE Journal April 2018 - 30
ITE Journal April 2018 - 31
ITE Journal April 2018 - Placemaking through a Traffic Signal Box Art Project: Effect of Artist Wrap to Cabinet Temperature
ITE Journal April 2018 - 33
ITE Journal April 2018 - 34
ITE Journal April 2018 - 35
ITE Journal April 2018 - 36
ITE Journal April 2018 - 37
ITE Journal April 2018 - 38
ITE Journal April 2018 - Shared Parking: Effective and Simple
ITE Journal April 2018 - 40
ITE Journal April 2018 - 41
ITE Journal April 2018 - 42
ITE Journal April 2018 - 43
ITE Journal April 2018 - 44
ITE Journal April 2018 - Relationship between Geometric Elements and Wrong-Way Crashes at Partial Cloverleaf Interchange Terminals
ITE Journal April 2018 - 46
ITE Journal April 2018 - 47
ITE Journal April 2018 - 48
ITE Journal April 2018 - 49
ITE Journal April 2018 - Professional Services Directory
ITE Journal April 2018 - 51
ITE Journal April 2018 - 52
http://www.nxtbook.com/ygsreprints/ITE/ITE_January2020
http://www.nxtbook.com/ygsreprints/ITE/ITE_December2019
http://www.nxtbook.com/ygsreprints/ITE/G110939_ITE_November2019
http://www.nxtbook.com/ygsreprints/ITE/G110110_ITE_October2019
http://www.nxtbook.com/ygsreprints/ITE/G110109_ITE_September2019
http://www.nxtbook.com/ygsreprints/ITE/G108559_ITE_August2019
http://www.nxtbook.com/ygsreprints/ITE/G108250_ITE_July2019
http://www.nxtbook.com/ygsreprints/ITE/G107225_ITE_June2019
http://www.nxtbook.com/ygsreprints/ITE/G104039_ITE_May2019
http://www.nxtbook.com/ygsreprints/ITE/G104038_ITE_April2019
http://www.nxtbook.com/ygsreprints/ITE/G104036_ITE_March2019
http://www.nxtbook.com/ygsreprints/ITE/G103582_ITE_February2019
http://www.nxtbook.com/ygsreprints/ITE/G102868_ITE_January2019
http://www.nxtbook.com/ygsreprints/ITE/G100155_ITE_December2018
http://www.nxtbook.com/ygsreprints/ITE/G100154_ITE_November2018
http://www.nxtbook.com/ygsreprints/ITE/G99495_ITE_October2018
http://www.nxtbook.com/ygsreprints/ITE/G98028_ITE_September2018
http://www.nxtbook.com/ygsreprints/ITE/G97366_ITE_August2018
http://www.nxtbook.com/ygsreprints/ITE/G96287_ITE_July2018
http://www.nxtbook.com/ygsreprints/ITE/G94315_ITE_June2018
http://www.nxtbook.com/ygsreprints/ITE/G93877_ITE_May2018
http://www.nxtbook.com/ygsreprints/ITE/G93065_ITE_Apr2018
http://www.nxtbook.com/ygsreprints/ITE/G91484_ITE_Mar2018
http://www.nxtbook.com/ygsreprints/ITE/G89434_ITE_Feb2018
http://www.nxtbook.com/ygsreprints/ITE/G86608_ITE_Jan2018
http://www.nxtbookMEDIA.com