62
Therefore, employing the crash model for vehicle-pedestrian/cyclist, the probability distributions for the
different crash severities, and the societal costs for the different crash severities, the cost of vehicle-
pedestrian/cyclist crashes for the different available speed limits is shown below.
Speed Limit
(mph)
No. of Ped/
Cyclist
Crashes
Crash Costs by Severity ($)
K A B C O Total
20 6.7 62,820 52,664 63,787 91,982 3,364 274,617
25 4.3 57,509 43,306 46,491 58,149 1,809 207,263
30 2.7 52,516 35,024 33,455 36,324 962 158,280
35 1.8 47,233 27,963 23,752 22,435 505 121,888
40 1.1 41,618 22,033 16,652 13,691 262 94,256
45 0.7 36,368 17,124 11,524 8,256 134 73,407
50 0.5 31,385 13,136 7,869 4,920 68 57,378
55 0.3 26,684 9,948 5,303 2,897 34 44,867
60 0.2 22,395 7,431 3,528 1,686 17 35,058
It is noted that under this particular crash model, the number of pedestrian and cyclist crashes
decreases as the speed limit increases. This is likely due to the fact that higher speed roads have lower
pedestrian and cyclist traffic than similar lower speed roads. In other words, exposure to these types of
crashes decreases as speed increases.
The same methodology is employed to identify the societal cost of vehicle-vehicle crashes for the
different speed limit alternatives.
Speed Limit
(mph)
No. of Vehicle-
Vehicle
Crashes
Crash Costs by Severity ($)
K A B C O Total
20 19.4 — 2,256 5,145 32,599 46,386 86,386
25 17.0 114,456 2,378 6,419 35,916 39,842 199,011
30 14.9 20,101 3,132 8,073 39,551 33,984 104,839
35 13.1 26,475 4,583 9,655 42,183 28,884 111,780
40 11.5 38,746 5,902 11,698 44,883 24,322 125,552
45 10.1 54,437 7,303 13,617 46,323 20,402 142,082
50 8.9 74,689 9,102 15,970 47,593 16,910 164,265
55 7.8 97,064 11,262 17,983 47,578 13,957 187,845
60 6.8 126,696 14,037 20,257 47,229 11,353 219,572
It is noted that the number of crashes decreases as the speed limit increases. This is likely due to the fact
that the design of higher speed roads affords more generous dimensions and greater safety features
than similar lower speed facilities.