Mirrors
Convex Mirror Placement: Distance + Height + Angle Spec
Cojo
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6 min read
Mirror placement is geometry. A correctly sized mirror in the wrong position covers nothing useful; a slightly oversized mirror in the right position covers everything that matters. The three numbers that determine whether a mirror solves the problem are viewing distance, mounting height, and tilt angle. This guide sets the practical ranges for the most common parking-lot, garage, drive-thru, and warehouse applications.
A convex parking-lot mirror is placed at a viewing distance of 4 to 7 times its diameter from the typical driver eye-line, mounted at 8 to 10 feet to mirror center for outdoor parking lots and garages, and tilted 5 to 15 degrees down from horizontal toward the driver eye-line at 4 feet 6 inches. Indoor warehouse aisles use 9 to 12 feet to mirror center; drive-thru queues use 7 to 9 feet. Cojo placed a 30-inch outdoor convex mirror on a Hillsboro grocery anchor pad blind corner in February 2026 at 9 feet to mirror center with a 7-degree downward tilt, covering a viewing distance of 14 feet to the cross-traffic point.
Effective coverage radius from a convex mirror is roughly 4 to 7 times its diameter at typical mounting height. The rule rolls out to:
| Mirror diameter | Effective viewing distance |
|---|---|
| 18 in | 6 ft to 11 ft |
| 24 in | 8 ft to 14 ft |
| 30 in | 10 ft to 18 ft |
| 36 in | 12 ft to 21 ft |
| 48 in | 16 ft to 28 ft |
Mounting height varies by application:
Tilt is the most-often misadjusted parameter. The right tilt aims the reflected scene at the driver's eyes, not at the ground or the sky.
| Mounting height | Driver eye-line | Recommended tilt |
|---|---|---|
| 8 ft | 4 ft 6 in (car) | 5 to 8 degrees down |
| 9 ft | 4 ft 6 in (car) | 7 to 11 degrees down |
| 10 ft | 4 ft 6 in (car) | 9 to 14 degrees down |
| 9 ft | 5 ft 6 in (forklift seat) | 5 to 8 degrees down |
| 11 ft | 5 ft 6 in (forklift seat) | 9 to 13 degrees down |
For a 90-degree blind corner, the optimal mirror position is on the far side of the corner from the approaching traffic, at about 3 to 5 feet of inside-corner offset. The offset gives the mirror a clear view of both directions of cross-traffic without one direction blocking the other.
For T-intersections and cross-aisles, the mirror sits on the wall directly opposite the approach direction, centered on the cross-aisle to give symmetric coverage of both perpendicular approaches.
For four-way intersections (warehouse), the mirror is suspended from the ceiling at the geometric center of the intersection, level with the ceiling structure.
After mounting, before final torque, verify the placement by walking the typical approach pattern at the driver eye-line height:
A mirror that fails sight-line verification on day one will fail it every day. The 5 minutes of verification before final torque eliminates the cost of a re-install later.
Some intersections need more than one mirror:
When using multiple mirrors, place each one at its own optimal viewing-distance, height, and angle for the specific approach it serves. Treating them as a single installation reduces effectiveness.
None of these mandate specific placement; they govern the underlying sight-line conditions that mirror placement is meant to address.
On a Hillsboro grocery anchor pad in February 2026, Cojo placed a 30-inch outdoor polycarbonate convex mirror at the southeast lot blind corner. Placement specs:
Sight-line verification at install confirmed the cross-traffic was visible from 32 feet at the start of the approach to within 6 feet of the corner. The corner has had zero reported near-miss incidents in the year since installation.
Mirror placement is geometry, and geometry is unforgiving. Five minutes of sight-line verification before final torque saves the cost of a re-install. Cojo specifies and places convex mirrors as part of property-management retrofit packages across the I-5 corridor. Contact Cojo for a placement assessment.
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