# SECTION 5

## Work Zone Examples

The example problems presented are intended to aid the analyst in understanding and computing road user cost impacts from various work zone scenarios. These examples represent the most common types of work zones a highway user may encounter. The NJDOT developed workbook/template is an easy-to-follow analytic tool that allows for a quick and flexible estimation of work zone road user costs.

## 5.1    Example #1 - Full-Time (24 Hour) Lane Reduction - Freeway

One eastbound lane of a six-lane freeway is undergoing rehabilitation. The eastbound lanes carry 50,000 vehicles per day of which 90% are passenger cars and 10% are trucks. A 3.0 mile work zone will be in place 24 hours a day until construction is complete. The normal posted speed of the facility is 55 mph and the speed through the work zone is posted at 45 mph. The normal capacity of the roadway is estimated at 6,300 vehicles per hour while the work zone capacity is estimated at 3,000 vehicles per hour. Compute the daily road user cost.

Answer      The Daily Road User Cost is \$45, 749 per day (2015 Dollars).

## 5.2    Example #2 - Off-Peak Hour Lane Reduction - Freeway

Using the information from Example 1, Compute the following:

A)      The daily road user cost when work zone is only permitted during the allowable off-peak lane closure hours of 9 AM to 3 PM and 8 PM to 6 AM.

B)      The Lane Occupancy Charge (LOC) associated with a 1-hour overrun in the allowable hours in part A.

Answer Part A     The Daily Road User Cost is \$4,391 per day (2015                               Dollars). Note the large reduction in Road User Costs                          when the work zone is not permitted during the peak                      hours.

Answer Part B     The Hourly Road User Cost for 6 AM to 7 AM is                            \$1,027 (2015 Dollars).

The rate per minute is \$17.11 (Round up to next \$10)

The Lane Occupancy Charge rate is \$20/minute

The Hourly Road User Cost for 3 PM to 4 PM is \$1,759               (2015 Dollars).

The rate per minute is \$29.31 (Round up to next \$10)

The Lane Occupancy Charge rate is \$30/minute

## 5.3    Example Problem #3 - Road Closure - Detour in Effect

A one-mile section of a two-lane coastal facility will be closed during a \$15 million bridge replacement project. The facility carries 25,000 vehicles per day of which 80% are passenger cars and 20% are trucks. A 9.0 mile detour will be in effect until construction is completed. The existing facility is posted at 55 mph and the average speed through the detour route is 35 mph. The normal capacity of the existing facility is 2,400 vehicles per hour and the detour route capacity is estimated at 1,900 vehicles per hour. Compute the daily road user cost incurred by the traffic traveling the detour

Answer      The Daily Road User Cost \$149,780 per day (2015 Dollars).                Note the large road user cost impact associated with long                 detours.

## 5.4    Example Problem #4 - Alternating Traffic Pattern - Two-Lane Highway

A two-lane facility in a central business district is undergoing resurfacing. The facility carries 10,000 vehicles per day of which 90% are passenger cars and 10% are trucks. A 0.5 mile alternating traffic work zone with flagmen will be in place around the clock until the resurfacing is completed. The facility is posted at 45 mph and the speed through the flagging zone is limited to 25 mph. Traffic Engineering estimates the flagging operation cycle time to be 6 minutes. The normal capacity of the two-lane facility is estimated at 2,400 vehicles per hour while the flagging work zone capacity is estimated at 750 vehicles per hour. Compute the daily road user cost.

Answer        The Daily Road User Cost is \$10,139 per day (2015 Dollars).

Last Document Correction:
September 1, 2015