Possible Clues:

• The drunken speedster is twice over it
• Credit cap
• I'm in a lighted setting as far as one can go
• One per customer, e.g
• I'm in lighted surroundings and that's 21 down
• See 61-Across
• Upper bound
• Put a lid on
• Maximum, e.g
• 70 miles per hour, on many interstates