It seems to me like road damage involves processes that happen deeper, for example those that create tire ruts in the lane. I'd guess the area should be counted as larger the deeper you go.
It seems plausible to me that if you drove trucks over an unlined parking lot completely randomly, then it would last much longer than when you run the same trucks on a highway lane.
It seems plausible to me that if you drove trucks over an unlined parking lot completely randomly, then it would last much longer than when you run the same trucks on a highway lane.