Impact of Road Work Zones on Traffic Flow and Safety: A VISSIM-Based Analysis of Driving Behavior and Risk Factors

To achieve Vision Zero and eliminate all fatalities and severe injuries in road traffic, it is necessary to improve road safety for both road users and road workers. Accidents and incidents that occur in work zones could be prevented by following national regulations and implementing measures such as putting up signs, barriers, and speed limits. Further, the work zone safety is closely related to driving behavior.

The aim of this study is to examine how work zones affect traffic flow and road safety with a focus on the Swedish driving behavior and national regulations. This study fills a research gap addressing the lack of simulation studies on work zones in Sweden. A literature study and interviews were conducted to present the regulations and understand the current situation regarding road safety. A case study area was observed and recorded in connection with a work zone. Machine learning was used to extract parameters from the Swedish traffic flow, which was used to calibrate a simulation scenario that correlated with a general Swedish work zone traffic flow. The model was improved by changing parameters that mimic a lower speed limit in the work zone and driving behavior with earlier merging.

It is found that Swedish drivers generally exhibit non-aggressive driving behaviors, including gap acceptance, adherence to speed limits, and early merging. There is a variation of risks of work zone safety, where several situations are believed to occur due to stressed drivers or a lack of information. Safety issues due to driving behavior were tested in the traffic simulation tool VISSIM, where an improved design simulation scenario illustrated a work zone where the speed limit was reduced and drivers merged earlier compared to the calibrated and adjusted scenario. The improvements impacted travel time by 2.2%, an insignificant increase compared to the enhanced safety to which the lower speed contributes.