Study reveals contributors to motorcycle crashes

From Quick Notes, Highway Safety Manager Brent Jennings

Note: In 2010, with the implementation of the Strategic Highway Safety Plan (SHSP), the committee has been committed to reducing fatal and serious injury motorcycle related crashes. One of the projects the team has been working on for the last several months is the Motorcycle Safety Fatality Summary, using crash report data from 2009-2010. The next step will be to include serious injury data. You should find the results surprising.

Lane Triplett, SHSP Motorcycle Team Member
For the past few months, I have been gathering data from the State of Idaho Vehicle Collision Reports for Motorcycles for the years 2009 and 2010. This project began during one of the initial planning sessions for the Idaho Strategic Highway Safety Plan (SHSP) Motorcycle Safety Committee. One of the strategies outlined was to analyze the data and identify some of the circumstances contributing to Idaho’s motorcycle fatalities. This analysis is a work in progress and more information and data will be added as it becomes available.

There were 34 fatalities in 2009 and 28 fatalities in 2010 included in 59 reports. Three reports include two victims. Five of the 62 fatalities were passengers. The following chart is a sampling of causation factors. Some crashes include one or more factors. While it is possible that some of the single-vehicle crashes may have been affected by an unreported animal or other vehicle, there is no data, physical evidence, or statements within the reports to support such occurrences. (Note: It is a coincidence that the totals for single- and multi-vehicle fatalities match the yearly totals.)

Single Vehicle Fatalities - 34
Multi-vehicle Fatalities – 28
Rider Error 27 Rider Error 16
Questionable RE 1 Driver Error* 12
Run-off Corner 22 Rider Violated Driver’s ROW 3
Wild Animal 3 Run-off Corner – Head-on Crash 3
Positive Alcohol/Drug Test 14 Rider Rear-ended Rider 3
Medical 1 Positive Alcohol/Drug Test 6**
Equipment 2    

* One of the 12 fatalities that were driver error had contributing line-of-sight issues. The signal operation at that intersection has since been changed.
** One of these was an intoxicated automobile driver and two riders were under the legal limit at .01and .024.

Of the total 62 fatalities, 43 were identified as rider error and 1 is questionable. This means up to 44 out of 62 were due to rider error. Eleven of the fatalities are without question the fault of another vehicle operator. This analysis does not include detailed information on serious injuries, levels of injury (A, B, C) or other involved crashes. There may be additional reports or information that would indicate the other driver to be at fault in some crashes.

It should be noted that 18 fatalities were out of state riders (16 riders, 2 passengers) and none of their endorsement information is known at this time. Of the 43 Idaho riders involved in fatal crashes, 26 had their motorcycle endorsement, and 17 did not. Two of the riders had no driver’s license at all, and 2 were riding on suspended licenses. Of the 43 Idaho riders, only 7 had taken a rider training course and one had failed. In three of these crashes, the rider survived but the passenger did not.

It is commonly believed that motorcycle fatalities are generally young men on sport bikes and/or riders not wearing helmets. Here is what the data tell us on these topics:

Ages of the Fatalities   Types of Motorcycles   Helmet Use  
Under 20 1 Cruiser/Tourer 45 Wore a Helmet 23
20-29 9 Sport Bikes 8 Novelty Helmet 2
30-39 9 Dual Sports 2 No Helmet 36
40-49 14 Off-Road 4 Unknown 1
50-59 16 Total 59 Total 62
60-69 10 Gender   Location  
70-79 2 Male 58 Rural 44
80-89 1 Female 4 Urban 15
Total 62 Total 62 Total 59

Of those 36 without helmets, 4 incident reports indicate severe head trauma. Of those 23 with helmets, 4 incident reports indicate head trauma. Actual causes of death were not available.

Primary conclusions from this initial analysis:

  • We (riders) are killing ourselves at a far greater rate than we had ever assumed (= 69 percent – 71 percent rider error)
  • 69% of victims are over 40 years old and 48 percent are between the ages of 40 and 59
  • Corners are the biggest killers (= 40 percent run off corner)
  • 39% of involved Idaho licensed riders did not have a motorcycle endorsement
  • Drugs and alcohol contributed in many cases (= 29 percent alcohol/drug involvement by riders)
  • Drivers violating riders’ right-of-way is also a contributing factor =18 percent )
  • Only 14 percent of involved Idaho licensed riders had passed a rider training course.

Published 7-11-2011