For every 2 hrs (morning + evening) you spent regularly on a hold, you spent 20 days in a year
For every 4 hrs, you spent 40 days.

People do leave their house as early as 5:00 am just to get to office by 7:00am in some parts of this country especially in Lagos and Abuja. That means that they spent nearly 2hrs or more on the road in the morning and same thing in the evening at the close of work. Most of these journeys are 10 to 20 mins drive on a non busy day.

(Now assuming you spent 1 hr in the morning and 1 hr in the evening, that becomes 2 hrs everyday
For 5 days in a week, you have 10 hrs and multiply that by 4 weeks, you have 40 hrs in a month. Also multiply by 12 months, you have 480 hrs in a year. Divide this by 24hrs, you have 20 days)