Retroreflective lettering and sign sheeting are made with tiny glass beads or prisms that send light back toward its source, so a sign lit by headlights appears bright to the driver behind them.
Ordinary reflective surfaces scatter light in all directions; retroreflective materials return it in a narrow cone toward the light, and the driver’s eyes sit close to the headlights. That is why road signs glow at night without lighting of their own.
Where parking needs it
- Regulatory and warning signs on drive aisles, entrances and ramps, which follow the MUTCD where it applies.
- Surface lots and garage roofs at night, where fixture light is low or uneven.
- Clearance bars, columns and curbs that drivers must avoid.
- Pavement markings, using reflective beads in the paint.
Good practice
- Choose sheeting grades suited to viewing distance and the sign’s purpose.
- Replace faded signs; retroreflectivity declines with age and sun exposure.
- Combine retroreflectivity with good legibility: letter height, contrast and spacing.
The Parkonomics view
A sign that cannot be read at night is not a sign. In parking, retroreflectivity is a cheap way to make wayfinding and safety signs work around the clock.
Related terms: MUTCD, Legibility, Readability, Wayfinding, Graphic Panel, Dynamic Signage