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Table 1 Roadway characteristics of all Iowa road segments stratified by crash status. N(%)*

From: The effects of roadway characteristics on farm equipment crashes: a geographic information systems approach

  Road segments
  Without a Crash (n = 318,368) With a Crash (n = 1,337) All Iowa Roads (n = 319,705)
Road characteristics
Traffic volumea
 0 – 30 68,068 (21.4) 123 (9.2) 68,191 (21.3)
 31 – 101 63,165 (19.8) 220 (16.5) 63,385 (19.8)
 102 – 360 62, 806 (19.7) 192 (14.4) 62,998 (19.7)
 361 – 1250 62,283 (19.6) 367 (27.5) 62,650 (19.6)
 1251+ 62,046 (19.5) 435 (32.5) 62,481 (19.5)
Speed limit (mph)
  < 35 118,946 (37.4) 156 (11.7) 119,102 (37.3)
 35 – 45 18,057 (5.7) 85 (6.4) 18,142 (5.7)
 50 – 60 173,207 (2.6) 1053 (78.8) 174,260 (54.5)
 65+ 8,158 (2.6) 43 (3.2) 8,201 (2.6)
Road type
 Interstate 5,323 (1.7) 6 (0.5) 5,329 (1.7)
 US Route 18,265 (5.7) 159 (11.9) 18,424 (5.8)
 Iowa Route 17,425 (5.5) 191 (14.3) 17,616 (5.5)
 FTM Routeb 62,962 (19.8) 569 (42.6) 63,531 (19.9)
 Local Route 214,393 (64.3) 412 (30.8) 214,805 (67.2)
Surface type
 Paved 190,576 (59.9) 930 (69.6) 191,504 (59.9)
 Unpaved 127,794 (40.1) 407 (30.4) 128,201 (40.1)
Road width
 mean(sd) 25.2 (7.3) 24.7 (5.8) 25.2 (7.3)
Shoulder width
 mean(sd) 4.2 (5.6) 7.4 (6.2) 4.2 (5.6)
  1. aAverage Annual Daily Traffic (Total annual traffic volume/365)
  2. bFarm to market route
  3. *P < 0.01 for all variables