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31 Table 3-20 describes the AADT data received and data · Illumination, sources for each state. For Wisconsin, New Jersey, and Illi- · Rumble strips, and nois, AADT data could not be obtained for each year of the · Delineation (e.g., chevrons and post-mounted delineators). study period. Estimation procedures, using the existing counts, were applied in the calculation of the missing AADT Since none of the data files received from the states con- volumes. tained information on these additional delineation and guid- None of the data files received from the study group states ance measures, the research team followed other data collec- contained information on the percentage of annual average tion strategies (see Table 3-21). nighttime traffic (i.e., annual average traffic between sunset Tables 3-22, 3-23, and 3-24 show the percentage of two- and sunrise). Permanent traffic counting stations (which col- lane treatment sites with and without illumination, additional lect continuous annual traffic counts) and average monthly delineation (e.g., chevrons and post-mounted delineators), sunrise and sunset times were used to estimate the percent- and shoulder rumble strips, respectively. age of annual average nighttime traffic at the various road- The states reported that chevrons are not placed on four- ways. lane freeways and expressways. However, post-mounted delineators are placed along freeways at a spacing of 60 to 100 ft (18 to 30 m). Less than 1 percent of four-lane freeway 3.2.6 Additional Delineation and Guidance Measures and expressway sites are illuminated. Tables 3-25 and 3-26 show the percentage of treatment Information was collected on the following additional delin- site length with and without shoulder rumble strips for free- eation and guidance measures: ways and expressways, respectively. TABLE 3-16 Summary information: environment type at four-lane freeway treatment sites State % of total % of total roadway length roadway length (urban) (rural) Missouri 19.1 80.9 New York 32.1 67.9 Pennsylvania 29.7 70.3 Wisconsin 12.6 87.4 TABLE 3-17 Summary information: lane widths at four-lane expressway treatment sites State % of total % of total % of total Minimum Maximum Average roadway roadway roadway lane width lane width lane width length when length length when (ft) (ft) (ft) lane width when lane lane width 12 ft = 12 ft Pennsylvania 11.0 78.9 10.1 8.0 25.0 12.4 Wisconsin 0.0 97.2 2.8 12.0 18.0 12.0 TABLE 3-18 Summary information: shoulder widths at four-lane expressway treatment sites State % of total % of total % of total % of total % of total Minimum Maximum Average roadway roadway roadway roadway roadway shoulder shoulder shoulder length length length length when length width (ft) width (ft) width (ft) when when when shoulder when shoulder shoulder shoulder width shoulder width width width > 8 ft and width 4 ft > 4 ft and > 6 ft and 10 ft > 10 ft 6 ft 8 ft Pennsylvania 54.0 6.1 21.3 8.9 9.7 0.0 12.0 4.8 Wisconsin 0.4 1.6 73.2 19.8 5.0 2.0 13.0 8.5
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32 TABLE 3-19 Summary information: TABLE 3-23 Percentage of two-lane environment type at four-lane expressway treatment sites with and without additional treatment sites delineation (chevrons or post-mounted delineators) State % of total % of total roadway length roadway length State % with % without (urban) (rural) additional additional Pennsylvania 18.6 81.4 delineation delineation Illinois 1.0 99.0 Wisconsin 11.6 88.4 New Jersey 1.0 99.0 New York 26.0 74.0 TABLE 3-20 AADT data and sources Pennsylvania 7.4 92.6 State Information Received Source Illinois AADTs for 1991, 1992, 1994, and 1997 to 2000 Highway Safety Information System TABLE 3-24 Percentage of two-lane (HSIS) treatment sites with and without Missouri AADTs for 1991 to 2001 Missouri DOT shoulder rumble strips New Jersey Short-term counting station data (downloaded New Jersey DOT from Internet)--various years State % with % without rumble rumble New York AADTs for 1991 to 2001 New York DOT strips strips Pennsylvania AADTs for 1991 to 2001 Pennsylvania DOT Illinois 0.0 100.0 Wisconsin Traffic count books for 1995, 1997, and 2000 Wisconsin DOT New Jersey 0.0 100.0 New York 0.0 100.0 TABLE 3-21 Additional delineation and guidance measures: data collection strategies Pennsylvania 6.6 93.4 State Data Collection Strategies Illinois Undertaking field visits TABLE 3-25 Percentage of four-lane freeway treatment sites with and Missouri Contacting DOT staff without shoulder rumble strips New Jersey Reviewing video-logs State % with % without New York Reviewing video-logs rumble rumble Pennsylvania Reviewing video-logs and contacting DOT staff strips strips Missouri 53.1 46.9 Wisconsin Contacting DOT staff New York 63.3 36.7 Pennsylvania 37.7 62.3 TABLE 3-22 Percentage of two-lane treatment sites with and without illumination Wisconsin 100.0 0.0 State % with presence % without of illumination presence of TABLE 3-26 Percentage of four-lane illumination expressway treatment sites with Illinois 7.1 92.9 and without shoulder rumble strips New Jersey 42.0 58.0 State % with % without New York 26.0 74.0 rumble rumble strips strips Pennsylvania 0.0 100.0 Pennsylvania 21 79 Wisconsin 100 0