The objective of a Texas Department of Transportation (TxDOT) research project was to develop guidance on intermediate access to and from buffer-separated managed lanes located within general-purpose lanes. For intermediate access openings, other communities recommend opening lengths between 1300 ft and 2000 ft [396 to 610 m]. While the recommended buffer width is 4 ft [1.2 m] or greater, many sites have a 2- to 3-ft [0.6 to 0.9 m] width. To assist in developing the guidance material, researchers recorded operations at five intermediate access sites. Examples of the characteristics measured included where the vehicle entered or left the managed lane (early, within one of two or three equal-distance zones, or late) and the lane of origin for the vehicle. A surprisingly large number of maneuvers (7 percent) were vehicles passing a slower-moving vehicle. Approximately 9 percent of those moving into the HOV lane and 8 percent of those moving out of the HOV lane crossed the solid white markings (i.e., were not in compliance with the pavement markings). The percent of non-compliance increased to about 15 percent during those periods with low speeds (less than 40 mph [64 km/h]) or high speeds (greater than 60 mph [96 km/h]). The percent of maneuvers in compliance with the pavement markings varied by the length of the intermediate access opening. The compliance rate was greater for the longer access opening length (1500 ft [457 m]) as compared to the 1160-ft [354 m] access opening length.
Samenvatting