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