Path Guidance Information in Advance of Work Zones at Urban Freeway Interchanges

Work activities at complex urban freeway interchanges often result in modified lane assignments and the temporary misalignment of existing overhead guide signs with the travel lanes. Thus, researchers conducted a driving simulator study to determine whether the location and accuracy of driver lane changes made in advance of major freeway-to-freeway interchanges were affected by the use of: (1) temporarily misaligned permanent guide signing, (2) temporary guide signing, and (3) route shield pavement markings. The results of this study verify that when the lane assignment arrows on existing overhead guide signs are covered and the signs are temporarily misaligned with the travel lanes, drivers are not clear which lane they need to be in to reach their destination and thus wait to make a lane change until closer to the exit ramp gore area. Thus, additional path guidance information presented to drivers in advance of the interchange can be beneficial. The results of the study also indicate that the use of smaller temporary lane assignment signs and/or route shield pavement markings upstream of the interchange encourages drivers to make their lane change further upstream of the exit ramp gore area. Thus, either of these devices or a combination thereof should be used to provide drivers with additional path guidance information in work zones where the existing overhead guide signs are temporarily misaligned with the travel lanes due to work activity and the lane assignment arrows are covered.