This lady is of a different generation. It's not that she misunderstands you in particular. When she was young it was a luxury and a privilege to be able to drive wherever. People who rode their bikes were few and far between.
Maybe she should walk more. Is there any (health) reason why she shouldn't?
as long as she's walking where it's safe it can only be a benefit for her and she might find she enjoys it.
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2008 Trek FX 7.2/Terry Cite X
2009 Jamis Aurora/Brooks B-68
2010 Trek FX 7.6 WSD/stock bontrager