I use note pad. It also matters what the track is actually made of, meaning asphalt, paint, concrete and etc. By changing the asphalt may not get you what you want, it all depends on how the track is designed. The surface may not actually be asphalt as many track makers use different things to get more than one groove in the track. Many tracks have an asphalt and concrete mix to get two grooves.
I looked at it in sandbox, and on Ace speedway 2005, the whole track is asphalt, here is the texture view from it. Grey is asphalt.
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