If the 30^th highest hourly volume is adopted for design, there will be congestion on road for only:

Explanation:

30th Highest Hourly Volume:

• It is the hourly volume that will be reached only thirty times or exceeded only 29 times in a year and all other hourly volumes of the year will be less than this value.
• 30th highest hourly traffic value is found to be satisfactory from the consideration of the facility as well as the cost. This is because the cost will be much lesser when compared to the peak hourly volume and there will be congestion only for 29 hours in the year and this is considered reasonable.
• The 30th highest hourly volume is generally adopted as the design hourly volume for the purpose of roadway facility design.

Important Points

Other Important Terms:

Average Annual Daily Traffic (AADT): The average 24-hour traffic volume at a given location over a full 365-day year, i.e. the total number of vehicles passing the site in a year divided by 365.

Average Annual Weekday Traffic (AAWT): The average 24-hour traffic volume occurring on weekdays over a full year. It is computed by dividing the total weekday traffic volume for the year by 260.

Average Daily Traffic (ADT): An average 24-hour traffic volume at a given location for some period of time less than a year. It may be measured for six months, a season, a month, a week, or as little as two days. An ADT is a valid number only for the period over which it was measured.

Average Weekday Traffic (AWT): An average 24-hour traffic volume occurring on weekdays for some period of time less than one year, such as for a month or a season.