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From page 91... ... the safety effectiveness of centerline rumble strips along varying roadway geometry. Also addressed in lesser detail is the safety effectiveness of dual applications of rumble strips (i.e., centerline and shoulder rumble strips installed along the same roadway section) Read the entire page →
From page 92... ... A similar site selection process was followed for the centerline safety evaluation as previously described for the shoulder rumble strip safety evaluation. The type of information gathered to determine whether sites from a particular state would be appropriate for this study included the following: • Has the agency installed centerline rumble strips covering the range of roadway types of interest for this study and has the agency installed any dual applications of both centerline and shoulder rumble strips at the same site (preferably installed in the same year) Read the entire page →
From page 93... ... Nontreatment sites in Minnesota identiﬁed during the safety evaluation of shoulder rumble strips were also used in the safety evaluation of centerline rumble strips. The videologs of the nontreatment sites were reviewed again as part of this safety evaluation to collect horizontal alignment data. Read the entire page →
From page 94... ... conﬁrm the absence/presence of the centerline rumble strips, (b) conﬁrm the absence/presence of both centerline and shoulder rumble strips, (c) Read the entire page →
From page 95... ... The main difference between the videolog data collection effort for the safety evaluation of centerline rumble strips compared to the safety evaluation of shoulder rumble strips is the collection of horizontal alignment data. Horizontal alignment data were speciﬁcally collected to assess the safety effectiveness of centerline rumble strips along varying roadway geometry. Read the entire page →
From page 96... ... Table 53 summarizes the basic layout of the available data in the three states for evaluation of the safety effectiveness of centerline rumble strips on speciﬁc types of roads. The data provided separately for each state, roadway type, and type of site are the number of sites, total site length, and mile-years. Read the entire page →
From page 97... ... Mile- years Number of sites Length (mi) Mile- years SRoNBA RS 0 0 0 Urban multilane undivided highways (nonfreeways) Read the entire page →
From page 98... ... Horizontal alignment. Table 57 provides the mileyears and number of horizontal curve sites and tangent sites, respectively, used to assess the safety effectiveness of centerline rumble strips along varying roadway geometry. Read the entire page →
From page 99... ... Before–after sites Nontreatment sites Before–after sites Nontreatment sites Before–after sites Nontreatment sites 9 – – – – – – 10 – – 48 68 – 33 11 36 20 313 304 61 96 12 251 218 208 155 74 71 13 7 5 7 17 – 2 14+ 7 – 24 59 – 4 a Includes data for all roadway types for which analyses are conducted. Read the entire page →
From page 100... ... More details on the analysis approach to quantifying the safety effectiveness of centerline rumble strips along varying roadway geometry are provided on the next page in Analysis Approach. Dual application sites. Read the entire page →
From page 101... ... Analysis Approach The EB methodology, as described in Section 6, Analysis Approach, was used to evaluate the safety effectiveness of centerline rumble strips on different roadway types and along varying roadway geometry. The evaluations included analyses of TOT, FI, and TOT target crashes. Read the entire page →
From page 102... ... 41.09122.00358.259387.831SRoNBA RS 74 25.50 90.64 222 2.44 7 0.08 6 0.07 PA NT No RS 85 40.70 407.01 1,168 2.87 82 0.20 17 0.04 13.0461.0209.69809.21SRoNBA RS 6 4.14 7.40 31 4.19 0 0.00 1 0.08 Urban two-lane roads WA NT No RS 22 4.39 21.95 43 1.96 0 0.00 1 0.23 30.05360.04679.0000,151.330,1SRoNBA RS 301 181.85 603.48 523 0.87 39 0.06 16 0.03 MN NT No RS 243 82.98 747.82 445 0.60 39 0.05 16 0.02 80.07632.090271.2639,141.398SRoNBA RS 526 180.78 722.28 1,256 1.74 54 0.08 40 0.06 PA NT No RS 518 236.40 2,364.01 4,140 1.75 301 0.13 117 0.05 80.05170.03152.292488.091SRoNBA RS 135 53.44 53.97 133 2.46 2 0.04 3 0.06 Rural two-lane roads WA NT No RS 215 69.85 349.25 967 2.77 19 0.05 28 0.08 Crash type All FI Head-on Sideswipe opposite-direction Roadway type State Site type Treatment status Number of sites Length (mi) Mile- years Total number of crashes Crash frequency (crashes/ mi/yr) Read the entire page →
From page 103... ... Horizontal Curve Sites 70.01190.05132.100260.261SRoNBA RS 135 28.41 93.07 98 1.05 9 0.10 2 0.02 MN NT No RS 105 14.89 134.04 113 0.84 7 0.05 7 0.05 60.0813.01458.184201.431SRoNBA RS 144 29.32 125.84 223 1.77 7 0.06 8 0.06 PA NT No RS 518 236.40 2,364.01 4,140 1.75 301 0.13 117 0.05 70.0350.0243.26980.14SRoNBA RS 62 10.42 11.02 27 2.45 1 0.91 1 0.09 Rural two-lane roads WA NT No RS 104 17.07 85.35 288 3.37 4 0.05 9 0.10 Tangent Sites 30.04260.09429.000890.178SRoNBA RS 166 153.44 509.87 425 0.83 30 0.06 14 0.03 MN NT No RS 138 68.09 612.79 332 0.54 32 0.05 9 0.02 40.0481.00221.253276.011SRoNBA RS 73 23.25 98.24 160 1.63 6 0.06 4 0.04 PA NT No RS 518 236.40 2,364.01 4,140 1.75 301 0.13 117 0.05 80.02170.01142.233308.941SRoNBA RS 73 38.55 42.95 106 2.47 1 0.02 2 0.05 Rural two-lane roads WA NT No RS 102 51.52 257.60 636 2.47 15 0.06 18 0.07 Table 61. Crash statistics for curve/tangent sites by roadway type, state, site type, treatment status, and severity (TOT crashes) Read the entire page →
From page 104... ... Horizontal Curve Sites 40.0670.02185.04960.261SRoNBA RS 135 28.41 93.07 34 0.36 2 0.02 1 0.01 MN NT No RS 105 14.89 134.04 42 0.31 4 0.03 2 0.02 20.0342.02381.185101.431SRoNBA RS 144 29.32 125.84 120 0.95 6 0.05 6 0.05 PA NT No RS 518 236.40 2,364.01 2,237 0.95 83 0.04 13 0.00 70.0320.0163.16580.14SRoNBA RS 62 10.42 11.02 10 0.91 1 0.09 3 0.27 Rural two-lane roads WA NT No RS 104 17.07 85.35 130 1.52 10 0.12 7 0.08 Tangent Sites 20.03140.05353.030390.178SRoNBA RS 166 153.44 509.87 159 0.31 13 0.02 8 0.02 MN NT No RS 138 68.09 612.79 137 0.22 19 0.03 5 0.01 30.0371.09142.173176.011SRoNBA RS 73 23.25 98.24 79 0.80 6 0.06 2 0.02 PA NT No RS 518 236.40 2,364.01 2,237 0.95 83 0.04 13 0.00 40.0650.0811.166108.941SRoNBA RS 73 38.55 42.95 53 1.23 2 0.05 1 0.02 Rural two-lane roads WA NT No RS 102 51.52 257.60 274 1.06 14 0.05 13 0.05 Crash type TOT FI TOT Target (head-on, sideswipe opposite-direction, and SVROR) Roadway type State Site type Treatment status Number of sites Length (mi) Read the entire page →
From page 105... ... Cross-sectional analyses using GLM were not used to assess the safety effectiveness of centerline rumble strips since all treatment sites had before-period information. Regarding the dual application sites, several sites were found during data collection that initially had shoulder rumble strips installed for several years, followed by the installation of centerline rumble strips. Read the entire page →
From page 106... ... Safety effectiveness results. For each crash type, roadway type, and state, the safety effectiveness of centerline rumble strips was estimated. Read the entire page →
From page 107... ... Table 66. Safety effectiveness of centerline rumble strips on TOT target crashes using the EB method. Read the entire page →
From page 108... ... Estimating the Safety Effectiveness of Centerline Rumble Strips Along Varying Roadway Geometry The same SPFs used to estimate the safety effectiveness of centerline rumble strips on different roadway types were used to estimate the safety effectiveness of centerline rumble strips along varying roadway geometry. Safety effectiveness results. Read the entire page →
From page 109... ... Table 69. Safety effectiveness of centerline rumble strips on TOT crashes at horizontal curve sites using the EB method. Read the entire page →
From page 110... ... Table 71. Safety effectiveness of centerline rumble strips on TOT target crashes at horizontal curve sites using the EB method. Read the entire page →
From page 111... ... Table 74. Safety effectiveness of centerline rumble strips on TOT target crashes at tangent sites using the EB method. Read the entire page →
From page 112... ... This observation is very likely due to limited sample sizes of the data. Summary of Key Findings The primary objectives of the safety evaluation of centerline rumble strips are as follows: • Quantify the safety effectiveness of centerline rumble strips on speciﬁc types of roads including urban multilane undivided highways (nonfreeways) Read the entire page →

From page 91...

... the safety effectiveness of centerline rumble strips along varying roadway geometry. Also addressed in lesser detail is the safety effectiveness of dual applications of rumble strips (i.e., centerline and shoulder rumble strips installed along the same roadway section)