Figure 4 is a histogram showing the various hours of lane closures/activity per day. This data was further stratified into three work zone subgroups:

1. Those with capacity impacts of 18 or more hours per day
2. Those that were active (or with lane closures) primarily at night
3. Those with capacity impacts primarily during daylight hours.

The X axis is hours (1-24) and the Y axis is Frequency.

Average nightwork activity per day is 9.6 hours
Average daytime activity per day is 9.5 hours
Average activities per day is 11 hours
Median activity per day is 10 hours

Back to figure 4