The use of dense-graded AC patches in porous friction surfaces causes a water damming effect at the patch which contributes to differential skid resistance of the surface. Low-severity dense-graded patches should be rated as medium severity due to the differential friction problem. Medium- and high-severity patches are rated the same.
|
|
L - Patch is in good condition and is performing satisfactorily. |
|
|
M - Patch is somewhat deteriorated and affects ride quality to some extent. Moderate amount of distress is present within the patch or has FOD potential, or both. |
|
|
H - Patch is badly deteriorated and affects ride quality significantly or has high FOD potential. Patch soon needs replacement. |
