I donβt know anything about this " mod-rewrite" you are talking about (maybe the Apache module?), But it looks like regex and I know about it. :-)
Try the following:
RewriteRule ^members/([^/]+)(/|)$ members.php?id=$1 [L]
, , ^ " ", "members/" , ([^/]+) "1 , , $1", (/|) " , $2", $ " ".