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<br />
<br />-----..
<br />
<br />Figure 6 summarizes the results of the test. An im-
<br />portant qualification to the results is that the ob-
<br />served parking count (Column 4) does not
<br />necessarily represent a "design value" for the devel-
<br />opment. It is not known if each project was operat-
<br />ing at maximum levels of trip generation or if
<br />business volumes were significantly lower for the
<br />project due to the slow economy or other factors.
<br />Specifically, it is known that those projects exhibiting
<br />an unusually low actual accumulation were being af-
<br />fected by site factors. Projects 10, 11, 13, 16, and 17
<br />were experiencing lower occupancy at hotel compo-
<br />nents. This is significant since the values in Column
<br />3 were computed assuming 100 percent occupancy.
<br />Further, some projects were surveyed assuming that
<br />all parking demand was being served by on-site facil-
<br />ities. Projects 13 and 15, however, may reflect a dif-
<br />ferent situation, since there is a substantial amount
<br />of "other" parking space available. For Project 13, it
<br />is known that such parking is used significantly by
<br />employees.
<br />
<br />
<br />.. :'<:;:'1ij.t3n~l(fll(i:!'?";'
<br />
<br />Findings
<br />
<br />With the above qualifications in mind, Figure 6 in-
<br />dicates:
<br />
<br />. The parking demand estimated by adding the indi-
<br />vidual peaks produced results that were consis-
<br />tently high.
<br />
<br />. Estimating shared parking demand using time dif-
<br />ferentials will, if properly constructed, be more re-
<br />liable than estimating gross parking demand.
<br />
<br />. When conservative values are used for peak park-
<br />ing and hourly factors, estimated shared parking
<br />demand will be higher than actual parking ac-
<br />cumulation. In addition, there often times are
<br />other relationships, such as captive market effects.
<br />which lower aggregate parking demand.
<br />
<br />"\".;0'"
<br />, ..' Figure 6
<br />Results" of Test Cases
<br />
<br />2
<br />
<br />Mixed-Use Project Type
<br />
<br />Estimated
<br />Single-Use
<br />Gross
<br />Peak
<br />Accumulation
<br />(spaces)
<br />
<br />Typical
<br />Zoning
<br />Code 1
<br />Requirement
<br />(spaces)
<br />
<br />. "~:i, ~~ '!': .
<br />
<br />3
<br />
<br />4
<br />
<br />5 6
<br />Percent of
<br />Overestimation
<br />Shared2
<br />Parking
<br />Peak
<br />to
<br />Actual
<br />
<br />7
<br />Percent
<br />Savings
<br />Gross
<br />Peak
<br />to
<br />Shared
<br />Peak
<br />
<br />Estimated
<br />Shared
<br />Parking
<br />Peak
<br />Accumulation
<br />(spaces)
<br />
<br />Observed
<br />Actual
<br />Peak
<br />Accumulation
<br />(spaces)
<br />
<br />Gross
<br />Peak
<br />to
<br />Actual
<br />
<br />1. Office/Retail 5,749 5.858 5,229 5,570 3% -6% 9%
<br />2. Office/Retail 2,936 3,744 2,788 2,352 25 19 6
<br />3. Office/Retail 772 900 617 633 22 -3 25
<br />4. Office/Retail 2,814 3,048 2,291 2,592 9 -12 21
<br />5. Office/Retail 162 196 154 154 5 0 5
<br />6. Office/Entertainment 1,458 1,879 1,326 1,163 25 14 II
<br />7. Office/Entertainment 812 1,016 714 464 75 54 21
<br />8. Office/Entertainment 1,724 2,112 1,501 614 181 144 37
<br />9. Office/Hotel 1,145 1,399 1,006 882 30 14 16
<br />10. Office/Hotel!
<br />Entertainment 1,627 1,933 1,323 725 124 82 42
<br />II. Office/Hotel!
<br />Entertainment 1,236 1,452 990 525 135 89 46
<br />12. Office/Hotel/
<br />Entertainment 784 862 659 809 -3 -19
<br />13. Office/Retail/Hotel!
<br />Entertainment 8,316 9,610 4,242 2,287 264 85 179
<br />14. Office/Retail!
<br />Entertainment 869 1,094 754 600 45 26 19
<br />15. Office/Retail/
<br />Entertainment 5,099 5,157 3,755 2,869 78 31 47
<br />16. Office/Hotel!
<br />Entertainment 2,588 3,188 2,183 1,498 73 46 27
<br />17. Office/Hotel 1,125 1,346 743 594 89 25 64
<br />(l)For this calculation, the following code standards were used: Office = 4,0 spaces per 1,000 square feet of GLA; retail = 4.0 or 5.0
<br />spaces per 1,000 feetofGLA (function of size); restaurant = 20.0 spaces per 1,000 square feetofGLA; residential = 1,0 spaces per
<br />dwelling unit; hotel = 1.0 spaces per room, with conference rooms at 0,5 spaces per seat.
<br />(2)Using results from Column 3.
<br />
<br />6 S e p t e m be r 83/ (!J]{Bfffi\'] [llj]]]I)
<br />
<br />31~n69
<br />
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