Vehicle intrusion crashes in highway work zones injure vehicle occupants and workers alike, and such crashes are the concern of both state agencies and highway contractors. This paper describes the results of an effort to develop prototypical scenarios of common work zone intrusion crashes documented in the New York State Department of Transportation work zone accident database. A prototypical scenario can be defined as one that is representative of the crash process because of the typicality of its chain of events and the likely causal relationships throughout the stages of the crash. By considering the chain of events that led to a particular crash, it is possible to group similar crashes and provide a more in-depth assessment, even though some of the facts involved in the individual crashes vary. In the study described here, prototypical scenarios were developed for four intrusion crashes at four types of work zone operations: lane closures, flagging operations, mobile operations, and traffic control setup and removal activities. It was concluded that a significant portion of intrusion crashes resulted from deliberate driver decisions and actions to enter the work space. The frequency of such deliberate events, which ranged from 25% to 64%, depended on the type of work operation in place on a given roadway. The study identified between three and eight prototypical crash sequences that were not the result of deliberate actions by drivers and that led to intrusion crashes.

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The merging taper lengths described in the Manual on Uniform Traffic Control Devices are assumed to apply to roadways of all types. Yet driver expectations and traffic operations differ greatly between the high-speed freeway and the lower-speed, signalized urban street. The research described in this paper investigated the operational impacts of reduced taper lengths on lower-speed urban arterials. The study found that drivers did react differently after merging taper lengths were modified. Both the merging taper and the work vehicle in the closed lane served as visual cues to drivers to vacate the closed lane. On longer taper lengths, channelizing devices were used to motivate drivers to change lanes. Vehicles with occluded views, however, were more likely to become trapped and to create mobility issues in the traffic stream. On shorter taper lengths, drivers reacted to the merging taper and the work vehicle itself. Although fewer vehicles became trapped near the merge point, that point was much closer to the work vehicle. Under the absence of taper conditions (i.e., mobile operations), in which the work vehicle was much larger than the trucks used during the merging taper observations, fewer drivers remained in the closed lane at comparable locations. Both motorist and worker safety must be considered in the selection of an appropriate merging taper length for work activities of shorter duration on urban arterials. Further research should investigate the implications for worker safety of installing and removing various merging taper lengths as compared with the time it takes to complete the work activity.

This paper documents the efforts and results of a human factors study of alternative business driveway channelizing treatments in work zones. The purpose of the research was to determine the effectiveness of alternative business driveway channelizing treatments over standard drum treatments. The alternative treatments included combinations of 18-in. low-profile longitudinal channelizing devices and 42-inch tall cones (i.e., grabber cones). Using paid participants who drove an instrumented vehicle, the researchers used driver eye-tracking equipment to compare differences in drivers' visual attention while approaching business driveways with the various channelization treatments deployed. Other measures of effectiveness considered were detection distance, percentage of missed driveways, driver perception and recall of treatments, and driver preferences. Although differences in the measures of effectiveness were less pronounced during the day, the alternative channelizing treatments generally performed better than the standard drum treatment at night.

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