Parking Studies and Layouts

Record the study boundary, count of marked usable stalls $N$, entry/exit time stamps or short-interval counts, vehicle identification method (where lawful), day type, weather, nearby events, motorcycles/accessible stalls and illegal/overflow parking. Use consistent study start/end cutoffs. Entries minus exits update accumulation, but counted parking events spanning either observation boundary must be treated explicitly before relating volume to mean duration. Field inventory should independently identify capacity lost to ramps, columns, exits, loading, accessible paths and prohibited stalls.

As a worked study assumption, a 200-stall facility open for 10 hours has $NT=2{,}000$ space-hours of observed capacity. With measured $P_L=1{,}180$ space-hours and $P_V=620$ consistently counted complete parking events, mean duration is $1.903$ hours/event, turnover is $3.10$ events/space, and average occupancy is $59.0\%$. These numbers cannot prove the lot lacked a severe short peak; demand could be concentrated into particular hours. If arrivals straddle the observation window or licence-plate matches are incomplete, adjust duration and volume treatment before relying on the identity $P_L=P_V\bar D$.

Obtain observed peak profiles by land use and time of week. For a new project, an estimated peak number of parked vehicles may follow $D=rX$ where $X$ is floorspace, employees, dwellings or other predictor and $r$ is an evidence-based, locally calibrated parking-generation rate. ITE's Parking Generation Manual, 6th edition supplies North American datasets; rates are not Philippine legal requirements or universal predictors. Account for walk, transit, motorcycle, delivery, special events, price, occupancy and local land-use mix.

An operational target such as 85% is a planning assumption for finding-space convenience, not a legal maximum. For demand $D=125$ vehicles and assumed $f=0.85$, target usable supply $N\ge\lceil125/0.85\rceil=148$ stalls. Compare this operational goal separately with actual local minimum/maximum parking ratios and required accessible inventory.

For a classroom 90° passenger-car scenario only, choose nominal stall width $b=2.5$ m, stall depth $d=5.0$ m and two-way aisle $a=6.0$ m. One opposing double-loaded module occupies $d+a+d=16.0$ m of cross-aisle width. These example numbers are not asserted to be universal Philippine minima, just as imported 9 ft × 18 ft stalls and 24-ft aisles are not universal Philippine rules. Obtain the current local zoning/building, traffic, fire access and accessible-parking requirements for each project; a design vehicle must pass swept-path tests at entries, ramps, aisle ends and turnaround points.

At $\theta=60^\circ$, $b=2.5$ m and $d=5.0$ m, ideal curb pitch is $p=2.5/\sin60^\circ=2.887$ m/space and perpendicular row depth is $h=5\sin60^\circ+2.5\cos60^\circ=5.580$ m. With an assumed manoeuvring aisle $a=5.5$ m, a double module depth would be $2h+a=16.660$ m. Aisle width is vehicle-, angle- and direction-dependent, and the 5.5-m example is not an approved minimum. Angled parking often uses directed one-way aisles but is not inherently prohibited from every other traffic pattern; approve the circulation plan through local regulations and swept-path simulation.

A rectangular parking sketch cannot demonstrate a car can actually enter or leave. Select a representative design vehicle (overall length/width, wheelbase, steering, overhang and turning radii) and simulate its outer body sweep and inside wheel path into stalls, around corners and at dead-end turnarounds. Maintain clearance to parked-car door zones, structural columns, pedestrians, kerbs, ramps and gates. Locate safe walking lines, lighting, signs, visibility triangles and pedestrian crossings outside conflicting turning movements where feasible.

The 2024 BP 344 amended IRR specifies an accessible parking slot minimum 4,000 mm wide × 5,000 mm long, an accessible walkway at least 1,200 mm clear between parked cars' front ends where described, locations near accessible entrances, appropriate dropped kerbs/ramps and firm, level surfaces; accessible bays should not be in sloping/ramped areas. Check the official figures and accompanying marking/signage provisions.

Selected accessible-space schedule (amended IRR, Table A.6.1):

For a 120-space project, the table indicates 5 accessible spaces under the stated schedule, before checking any other project- or jurisdiction-specific obligations. Verify the entire current table for facilities above 300 stalls; this excerpt intentionally does not paraphrase it into a universal percentage.

1. Survey representative times and distinguish measured demand from policy minimums and projected growth.
2. Forecast by local land-use context, trip alternatives and events, then calculate the hour-by-hour sum for genuinely shared parking. Separate peak summation exaggerates combined demand when use peaks differ; shared access also requires lease/operation agreements.
3. Test layout alternatives for usable capacity, manoeuvring, fire access, accessibility, loading, safe pedestrian routes and gate queues. A smaller stall arrangement that fails wheel-sweep or transfer clearance is not a valid efficiency gain.
4. Select operating policies (allocation, wayfinding, pricing, monitoring and enforcement) in light of local ordinances. An 85–90% target may be useful for management but is neither a fixed capacity law nor proof that all sites should use dynamic pricing.

• National Council on Disability Affairs, 2024 Revised Implementing Rules and Regulations of BP Blg. 344, Appendix A parking provisions.
• Department of Public Works and Highways, Amended IRR of BP 344 (official PDF), Appendix A §6 and Table A.6.1.
• Institute of Transportation Engineers, Parking Generation Manual, 6th edition (publisher resource; North American data, not Philippine law).