To help maintain your alertness while driving:

• Protect yourself from glare and eye strain with sunglasses
• Avoid heavy foods
• Be aware of your body’s natural “low” times
• All of the above
  Explanation:

  "To help maintain your alertness while driving: 1. Protect yourself from glare and eye strain with sunglasses. 2. Avoid heavy foods. 3. Be aware of your physiological downtime during the day (circadian rhythm). 4. Have another person ride with you, and take turns driving."