Time gaps are microscopic flow characteristics related to driver behavior, traffic safetyand capacity. Knowing time gap characteristics enables monitoring of traffic flow and takingappropriate safety measures, particularly in work zones. The objective of this study is to explorehow mean time gaps change based on vehicle type and traffic control treatment in single-lanework zones. For this purpose, thirteen data sets that involved over 8250 vehicle observationswere collected from six Interstate work zones in various traffic control conditions.In terms of vehicle type, trucks exhibited significantly greater mean time gaps than cars,possibly due to longer stopping distance they require compared to passenger cars. Besides, innearly half of the data sets, the mean time gaps of trucks following cars were significantlygreater than trucks following other trucks. Hence, the time gap preference of the truck driversdiffered significantly based on the vehicle type of their immediate leaders. On the contrary, suchdriving behavior was generally not observed in the car drives.Next, it is also essential to identify the effects of work zone traffic control treatments ontime gaps. In this study, the effects of flagger and Police presence were explored. According tothe results, the mean time gaps of all vehicle types increased significantly due to flaggerpresence. However, the mean time gaps of only cars following cars and trucks following carsincreased significantly due to Police presence. So compared to Police presence, flagger presencehad a more pronounced effect on spacing out vehicles, which led to a "safer" environment, butreduced number of vehicles processed.
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