Effectiveness of Changeable Message Displays in Advance of High-Speed Freeway Lane Closures

摘要

The field study evaluated the effectiveness of changeable message signing (CMS) devices in advance of freeway construction/maintenance zone lane closures. Operational traffic behavior and driver interview data were gathered in four states--South Carolina, Georgia, Colorado, and California. Before and after studies of baseline (no CMS) versus CMS application consistently demonstrated increased advanced prepatory lane change activity, smoother lane change profiles, significantly fewer late exits (within 100 ft of closure), and reduced speeds at the lane closure point to be associated with CMS use. The most preferable CMS location was found to be 3/4 mile in advance of the lane closures. Of three tested device types (1-line bulb matrix, 2-line rotating drum, and 3-line bulb matrix), the large, obtrusive 3-line bulb matrix tended to produce more advance lane change behavior; however, no difference in the hazardous late exit maneuvers was observed between types. All three were equally effective in eliciting speed reductions at the entrance to the lane closure. Driver interview data tended to favor the 3-line device because of its greater information display capacity. Message combinations of speed, lane closure, and merge advisories were tested on the devices. Although lane change behavior of the total traffic stream did not significantly differ between message conditions, interviewed motorists favored the speed and lane closure message combination as being most helpful, providing most response time, and meeting information needs.