Historical clue formulations

• It's between an A and a B — 2018-09-06
• A- — 2017-01-22
• No longer an octogenarian — 2016-11-01
• What a leadfoot may do — 2013-10-19
• The number XC — 2011-12-19
• It's dangerous to do on the road — 2011-02-12
• Number of feet between baseball bases — 2007-04-17
• You can get cited for doing it — 2005-02-12
• You may be stopped for doing it — 2004-10-16
• Nonagenarian's age — 2003-03-31
• Lowest A, usually — 1997-09-11
• Octogenarian's goal in life? — 1994-10-21