Freeway Exit Lane Drops in Texas (1292-1F)

This project determines how motorists interpret or respond to various sign and pavement marking alternatives they may or may not have experienced before. Motorist interpretation of signs and markings were obtained through surveys, while field observations were used to measure actual motorist responses to pavement markings.|The results from both surveys indicate that motorists have a high level of understanding of the yellow EXIT ONLY panel. Drivers do not understand the use of the white arrow next to a yellow EXIT ONLY panel as well. Over one third of the participants incorrectly interpreted the meaning of the white arrows. Motorists prefer the use of diagrammatic signs as the first of several signs indicating an approaching exit lane drop and the use of the conventional black on yellow panel close to the exit lane drop. Texas motorists understand the meaning of the wide solid white line.|The field studies demonstrate that the installation of lane drop markings can cause a shift in motorist lane change locations in advance of a lane drop. One site's data directly reveals while the other site's data indicates that drivers move into or out of the exiting lane further upstream of the lane drop in the period after markings were installed than in the period before markings were installed. For the 800 feet (244 m) immediately upstream of the gore at one site, fewer vehicles left the exit lane in the after period than in the before period, while in the area between 1700 and 1000 ft (518 and 305 m) upstream of the gore, more vehicles left the exit lane in the after period than in the before period. The before-and-after studies also reveal that the number of erratic maneuvers within the entire study segment decrease with the installation of markings.