Table 2 Description of the variables in the assembled dataset

Numerical

Elapsed time

E

month

12 values (E₀, E₁, E₂, E₃, E₁₁, E₁₂, E₁₅, E₂₁, E₂₄, E₂₇, E₃₃, and E₃₆). E₀ represents the month of installation, E₁ represents 1 month since installation, E₁₁ represents 11 months since installation, and similarly for other values

Measured Rs

MR_S

mcd/m²/lux

12 values (MR_S0 through MR_S36, corresponding to E₀ through E₃₆)

Cumulative traffic level

TR

vehicles

12 values (TR₀ through TR₃₆, corresponding to E₀ through E₃₆)

Cumulative snowfall

SN

in

12 values (SN₀ through SN₃₆, corresponding to E₀ through E₃₆)

Marking thickness

TH

mil

172 unique values of marking thickness

Categorical

Surface type

S

-

2 unique categories (asphalt and concrete)

Types of marking material

T

-

7 unique categories (waterborne paint, thermoplastic, preformed thermoplastic, permanent polymeric tape, epoxy, polyurea, and MMA)

Marking color

C

-

2 unique categories (white and yellow)

Marking manufacturer

M

-

30 unique categories (M1 through M30)

Bead type of the first drop

b

-

7 unique categories (Type 1, Type 2, Type 3, Type 4, high-performance beads, wet reflective elements, and N/A. Here, N/A represents only one type of glass bead was applied as the second drop)

Bead type of the second drop

B

-

7 unique categories (Type 1, Type 2, Type 3, Type 4, high-performance beads, premium optics “Utah blend”, and N/A. Here, N/A indicates marking does not have dropped on glass beads)