I'm terrible, at first glance of the thread title, I thought you were talking about amphetamines or something...
Speed can cause anxiety, certainly. But it's by no means an AS-related trait. My NT girlfriend is paralyzed if she tries to drive faster than 30mph. I however, love to drive fast. I mean, not dangerously fast, but... efficiently fast.
Stupid, dangerous drivers cause me anxiety. These are the people who weave in and out of traffic, or are hopelessly lost and cut across three lanes unexpectedly, etc, etc. I get awful anxious road rage if I have to drive in heavy, unpredictable traffic. Otherwise, I'm fine.
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Plantae/Magnoliophyta/Magnoliopsida/Fabales/Fabaceae/Mimosoideae/Acacia