Parking lot lighting requirements
The current IES recommendation for all parking lots is an average of 0.2 fc (2 lux) on the pavement, with the maximum no more than 4 times the average, and an average vertical illuminance of 0.1 fc (1 lux) at 5 ft. That is ANSI/IES RP-8-25, Table 17-1. The previous edition, RP-8-18 with Addendum 1, set the same 0.2 fc as a minimum, with Max:Min 20:1. Many guides still quote the older minimum. Local codes and ordinances can replace either.
RP-8-25 and RP-8-18 side by side
| Criterion | RP-8-25, Table 17-1 | RP-8-18+A1, Table 17-2 |
|---|---|---|
| All parking lots, horizontal, at grade | 0.2 fc (2 lux) average | 0.2 fc (2 lux) minimum |
| Horizontal uniformity | Max:Avg 4:1 or less | Max:Min 20:1 or less |
| All parking lots, vertical, at 5 ft | 0.1 fc (1 lux) average | 0.1 fc (1 lux) minimum |
| Vertical uniformity | Max:Avg 20:1 or less | Max:Min 20:1 or less |
| Transaction areas, before curfew | 0.9 fc (10 lux) minimum horizontal, 0.5 fc (5 lux) minimum vertical, Max:Min 15:1 (both editions) | |
| Transaction areas, after curfew | 0.2 fc (2 lux) minimum horizontal, 0.1 fc (1 lux) minimum vertical, Max:Min 15:1 (both editions) | |
| Pay machines, vertical on the front face | 2.8 fc (30 lux) before curfew, 1.4 fc (15 lux) after (both editions) | |
| EV charging stations | New: 3 to 20 fc average by activity level and lighting zone | No separate rows |
Both tables cover parking lots and the top floor of parking garages, are titled as basic requirements and not for areas where security is an issue, and give values to be maintained over time, so the design includes a light loss factor. The parking-lot rows apply to lighting zones LZ1 to LZ4 (table note 1).
How the standard says to calculate it
- Horizontal grid: the entire parking pavement, points no farther apart than one third of the mounting height, starting within half a grid spacing of the boundary (RP-8-25, 17.4.3.1).
- Vertical points: 5 ft above grade, at least on the drive-aisle centerline, spaced no more than one third of the mounting height, facing the directions of vehicle travel, each direction assessed separately (17.4.3.2).
- Not outward: vertical values are not required facing out along a boundary or beyond the outer line of luminaires (17.4.3.2).
- Maintained: the values are to be maintained over time (table note c), so calculations include a light loss factor.
A worked example
The 300 × 200 ft lot on our homepage: 8 poles of a 166 W Type III at 30 ft, light loss factor 0.9, horizontal points every 10 ft (one third of the mounting height), vertical points at 5 ft on the aisle centerline in both directions.
| Check | Result | RP-8-25 | RP-8-18+A1 |
|---|---|---|---|
| Horizontal, 651 points | min 0.25 · avg 2.20 · max 4.36 fc | avg ≥ 0.2: yes | min ≥ 0.2: yes |
| Horizontal uniformity | Max:Avg 2.0 · Max:Min 17.6 | ≤ 4: yes | ≤ 20: yes |
| Vertical, one direction | min 0.11 · avg 0.51 · max 1.39 fc | avg ≥ 0.1, Max:Avg 2.7: yes | min ≥ 0.1, Max:Min 12.5: yes |
| Vertical, other direction | min 0.23 · avg 2.05 · max 4.17 fc | avg ≥ 0.1, Max:Avg 2.0: yes | min ≥ 0.1, Max:Min 17.8: yes |
This layout was searched against the RP-8-18+A1 form (minimum 0.2 fc, Max:Min 20). Its average is 11 times the RP-8-25 average, so a layout searched against RP-8-25 values could use fewer poles. Runnax Engine searches on a minimum and a Max:Min ratio today; it reports the averages, so RP-8-25 values are checked from the results. These are simulations, direct light only, and not a compliance statement. Pole counts for other lot sizes.
What the IES tables are not
- Not law. RP-8 is a recommended practice. Its table notes say codes, ordinances or mandates may supersede the values and that the designer makes the final determination of criteria.
- Not security lighting. Both tables are for basic requirements. For security, RP-8 points to IES G-1.
- Not OSHA. The often-quoted OSHA table (29 CFR 1926.56, Table D-3) covers construction areas while work is in progress and does not mention parking lots.
Questions
What are the IES foot-candle requirements for a parking lot?
IES RP-8-25 (Table 17-1) recommends, for all parking lots, an average of 0.2 fc (2 lux) on the pavement with a maximum-to-average ratio of 4:1 or less, and an average vertical illuminance of 0.1 fc (1 lux) at 5 ft with Max:Avg 20:1 or less. Pedestrian and vehicle transaction areas have higher values: 0.9 fc minimum before curfew.
Is it 0.2 fc minimum or 0.2 fc average?
It depends on the edition. RP-8-18 with Addendum 1 (Table 17-2) set 0.2 fc as the minimum with Max:Min 20:1. RP-8-25 (Table 17-1) keeps 0.2 fc but as an average, with Max:Avg 4:1. Many pages still quote the older minimum. Use the edition your specification or authority names.
Are the IES values a legal requirement?
No. RP-8 is a recommended practice. Its own table notes say codes, ordinances or mandates may supersede the values and that the designer makes the final determination of criteria. Check the code and permit rules where the lot is.
Does OSHA set parking lot lighting levels?
The OSHA illumination table that is often quoted, 29 CFR 1926.56 Table D-3, applies to construction areas while work is in progress. It does not mention parking lots.
What does RP-8-25 recommend for EV charging stations?
RP-8-25 adds EV charging stations to the parking-lot table, with average targets that depend on activity level and lighting zone, from 3 fc to 20 fc. RP-8-18 with Addendum 1 has no separate EV rows.
Where is vertical illuminance measured?
At 5 ft above finished grade, at least on the drive-aisle centerline, in the primary directions of vehicle travel, with each direction assessed separately (RP-8-25, Section 17.4.3.2).
Can Runnax check my lot against these values?
Yes. A run reports the minimum, average and maximum on every grid point and the vertical values on the aisle, so both editions can be checked. The engine searches on a minimum and a Max:Min ratio; RP-8-25's average-based values are checked from the reported results, not yet searched on.
Sources
- ANSI/IES RP-8-25, Recommended Practice: Lighting Roadway and Parking Facilities, Part 2, Chapter 17, Table 17-1 (page 17-10), and Sections 17.4.3.1 and 17.4.3.2. Illuminating Engineering Society, 2025.
- ANSI/IES RP-8-18+A1, Design and Maintenance of Roadway and Parking Facility Lighting, Chapter 17, Table 17-2. Illuminating Engineering Society.
- 29 CFR 1926.56, Illumination, osha.gov.
Values are quoted from the published documents for reference. Your specification, code or authority having jurisdiction decides which edition and which values apply.