In dry daylight, paint and raised pavement markers (RPMs) are both easy to see. In wet darkness, paint disappears and RPMs do not. That single fact drives the choice on every Oregon parking lot that sees rain, fog, dawn, or dusk traffic. Below is the side-by-side, with FHWA-cited evidence and a real Salem install we ran in March 2026.
Quick verdict
For most Oregon parking lots, a hybrid is the right answer: paint provides daytime delineation and dotted-line continuity, RPMs provide wet-night and end-of-life backup. Paint alone fails at night in rain. RPMs alone are not a substitute for painted lines on most code-compliant lots.
Why does paint disappear in rain?
Traffic paint is visible because of glass beads embedded in or sprinkled on the wet film. Headlight light hits the bead, refracts into the paint, bounces off the white pigment, and returns to the driver's eye. When water pools over the bead, the light path is disrupted -- the wet glass film acts like a mirror that reflects light away from the driver. The Federal Highway Administration documents this loss in its wet-reflective pavement marking research, which shows wet-night retroreflectivity dropping by 60 to 90 percent compared with dry conditions.
Why do RPMs stay visible in rain?
A raised pavement marker sits 0.4 to 0.8 inches above the pavement. Water pools below the lens face; the lens stays clear and continues to retroreflect headlight light. The retroreflectivity coefficient is measured in millicandelas per lux per square meter (mcd/lux/m^2), and FHWA publishes minimum maintained levels in its retroreflectivity policy.
Side-by-side comparison
| Attribute | Paint | RPM |
|---|---|---|
| Daytime visibility (dry) | Excellent | Good |
| Daytime visibility (wet) | Good | Good |
| Nighttime visibility (dry) | Good | Excellent |
| Nighttime visibility (wet) | Poor | Excellent |
| Tactile cue when crossed | None | Yes |
| Service interval | 12 to 24 months | 2 to 7 years |
| Per-linear-foot cost (install) | Low | High |
| Snowplow vulnerability (raised) | Wears with sweeper | Damaged unless flush |
| MUTCD compliance | Required for line striping per Part 3 | Supplemental per Section 3B.11 |
| Standards | ASTM D2243, federal traffic paint specs | ASTM D4280 |
Real install: Salem retail center
A 14,000-square-foot Salem retail center hired Cojo in March 2026 after the property manager logged 23 wet-weather complaints over 18 months -- drivers reporting they could not see lane lines in rain. The lines were painted, age 14 months, fading on the order of 25 percent retroreflectivity loss but still within the manufacturer's stated service interval. We left the painted dotted lane indicators in place and added raised reflective polycarbonate RPMs at 40-foot spacing along each lane line. Wet-weather visibility complaints dropped to zero across the next 14 months. Paint was scheduled for re-application at month 18 per the original maintenance plan; the RPMs continue to provide visibility through the new paint cycle.
When to choose paint alone
- Indoor garage or covered lot with no rain exposure
- Very low-traffic stub lot where re-striping every 12 to 18 months is acceptable
- Tight budget where the per-linear-foot delta to RPMs is prohibitive
When to choose RPMs alone
Rarely. RPMs alone do not satisfy MUTCD line-marking requirements on public roads. For private parking lots they can be used in low-speed access drives where painted lines are visually unhelpful, but most situations call for a combined approach.
When to choose paint + RPMs
Most commercial and institutional parking lots:
- Lane lines on main aisles (paint + RPMs at 40 to 80-foot spacing)
- Stop-bar leading edge (RPMs ahead of painted bar)
- Drive-thru queue line (paint + RPMs every 30 feet)
- Edge lines on entry drives at night (paint + RPMs along curb)
- Fire-lane edge legend (paint legend + RPMs on edge)
Cost comparison: paint vs paint + RPMs
Industry Baseline Range
| Component | Range |
|---|---|
| Painted 4-inch lane line | $0.12 to $0.35 per linear foot |
| Raised reflective RPM at 40-ft spacing | $3 to $9 per marker (or $0.08 to $0.23 per linear foot of lane) |
| Combined paint + RPMs at 40 ft | $0.20 to $0.58 per linear foot |
| Snowplowable RPMs at 40-ft spacing | $14 to $28 per marker ($0.35 to $0.70 per linear foot of lane) |
Current Market Reality
2026 paint pricing has been steady; RPM pricing has risen with polycarbonate and bitumen costs. The crossover point at which adding RPMs costs less than re-striping paint twice as often shows up around the 18-month re-stripe interval. Lots that need annual re-striping pencil out to RPMs almost immediately. For more on the underlying line-striping economics see our line striping cost guide.
Hybrid layout strategies
The most cost-effective strategy on a typical lot: full painted layout (lines, legends, ADA, fire lane), then RPMs added only on the wet-night critical paths -- main aisles, stop bars, and entry/exit edges. The RPMs survive multiple paint cycles, so the second and third re-stripes are paint-only.
For wet-rated marker selection see best pavement markers for wet-night visibility, and for cost detail see pavement marker cost guide.