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71 TABLE 32 Fatal-and-injury median opening accident frequency by median opening type Median opening accident Median opening a Median Number frequency accident frequency opening of median (for entire study period) (per median opening per year) type openings U-turn Left-turn Total U-turn Left-turn Total URBAN ARTERIAL CORRIDORS Midblock 1a 7 1 0 1 0.029 0.000 0.029 2b 20 1 2 3 0.010 0.020 0.030 2c 10 1 0 1 0.020 0.000 0.020 Three-leg 3a 11 1 3 4 0.018 0.055 0.073 3b 19 0 13 13 0.000 0.143 0.143 3c 2 0 6 6 0.000 0.600 0.600 4a 4 0 4 4 0.000 0.174 0.174 Four-leg 5a 8 0 10 10 0.000 0.250 0.250 5b 17 0 24 24 0.000 0.270 0.270 6a 5 2 25 27 0.067 0.833 0.900 RURAL ARTERIAL CORRIDORS Midblock 1a 7 0 2 2 0.000 0.059 0.059 Three-leg 3a 4 0 1 1 0.000 0.059 0.059 Four-leg 5a 1 0 0 0 0.000 0.000 0.000 a The study period was generally five years in duration. However, only four years of accident data were available for sites in New Jersey, and six years of accident data were available for sites in New York. opening accident rate at median openings with either no left- MEDIAN OPENING CONFLICT RATES turn lane or only one left-turn lane, but the data reflect only two median openings of Type 3c. Furthermore, the data showed An analysis of traffic conflicts was conducted and is considerable state-to-state variation that could not be accounted described in Chapter 5. The videotape recordings made dur- for with a database of this size. Comparing median openings at ing the field data collection effort were reviewed to document three-leg intersections, average median opening accident rates how drivers behave in making U-turns and left turns through for directional three-leg median openings are about 48 percent unsignalized median openings. Three basic conflict types lower than the accident rates for conventional three-leg median were observed and analyzed: openings. Comparing median openings at four-leg intersec- tions, average median opening accident rates for directional Conflict Type A: A vehicle turning from the major road four-leg median openings are about 15 percent lower than for conventional four-leg intersections. into the median opening causes the following vehicle on For rural arterial corridors, the average median opening the major road to brake. Conflict Type B: Conflict between two or more vehicles accident rate is lower for median openings at three-leg inter- sections than for median openings at four-leg intersections. within the median opening. Conflict Type C: A vehicle turning from the median However, the sample size of median openings and median- opening-related accidents for rural arterial corridors is so opening onto the major road causes the vehicle on the small that no firm conclusions can be drawn. major road to brake. Comparable results for fatal-and-injury and property- damage-only accident rates at median openings are presented Table 38 summarizes traffic conflicts by median opening in Tables 36 and 37. type. Some observations from the table are as follows: