Motorcycle Licensure, Ownership, and Injury Crash Involvement
-ewX-.,
lzw ;llKIl'-ll;--.-l;z.-X-H:.
Jess F. Kraus, PhD, Craig Anderson, DHSc, Paul Zador, PhD, Allan Wdliams, PhD, Shakeh Arzemanian, MPH, Weichang Li, MA, and Michael Salatka, MPH
Introdudtion In most states a special license is required to operate a motorcycle on public streets and highways. There is evidence, however, that many of the motorcycle drivers killed or seriously injured in crashes did not have a license to operate a motorcycle. Hurt and associates* reported in an unpublished document that 46 percent of 900 motorcycle drivers involved in crashes in Los Angeles in 1976-77 were not validly licensed. Data from the US Department of Transportation's Fatal Accident Reporting System (FARS)** show that about 43 percent of motorcyclists killed on public roads or highways in the United States did not hold a valid motorcycle operator's license. In both reports, however, there was no information given on licensure status of motorcyclists not involved in injury crashes. Neither of these data sets provides information on whether the injured were driving motorcycles they owned, nor do they indicate whether lack of licensure was associated with increased crash risk. Barry' noted 20 years ago that a substantial percentage of operators of motorcycles involved in injury crashes had "borrowed" the vehicle, but the report did not include information on whether the motorcyclists were licensed. The present study was designed to address the following questions: * Do motorcycles owned by people without motorcycle licenses have greater likelihood of crash involvement? * To what extent do motorcycle drivers in serious and fatal injury crashes have valid licenses? own the motorcycle they were driving?
* How does motorcycle licensure vary by whether the crash-involved driver owned the motorcycle ("driver-owner" vs. "driver-nonowner")? * How is motorcycle licensure affected by the relationship between crashinvolved driver-nonowners and owners, when other relevant factors are also controlled?
Methods A valid motorcycle license in California is a "class 4" license or, more frequently, a motorcycle endorsement to another class of license. Motorcycle licensure requires a written examination and driving test for two-wheeled vehicles. Motorcyclist training was not required for any drivers prior to 1988.2
Crash-Involved Motorcycles Motorcycle crashes that occurred between July 1, 1985 and October 31, 1986 *Hurt et al: Motorcycle accident cause factors and identification of countermeasures. Traffic Safety Center, University of Southern California, Los Angeles, 1981. **Buchanan L: Presentation at Transportation Research Board Meeting, Washington, DC, 1988.
Address reprint requests to Jess F. Kraus, PhD, Department of Epidemiology, School of Public Health, UCLA, Los Angeles, CA 90024-1772. Co-authors Anderson, Arzemanian, Li, and Salatka are also at UCLA. Dr Zador and Dr Williams are with the Insurance Institute for Highway Safety, 1005 N. Glebe Road, Arlington, VA 22201. This paper, submitted to the Journal February 28, 1990, was revised and accepted for publication June 14, 1990.
February 1991, Vol. 81, No. 2
Motorcyde Licensure, Ownership, and Injury Crash Involvement Owners of Motorcycles Not in Crashes (Comparison Group)
on a California road, street, or highway were identified using the California Highway Patrol (CHP) Statewide Integrated Traffic Records Systems (SWITRS) and the original police reports. Crashes analyzed were limited to those in which the motorcycle driver was fatally or severely injured. A severe injury was defined by the CHP3 as a cut or laceration of skin from which blood flows freely or saturates clothing, and also includes an extremity not in normal position, indicating fracture. In almost all cases, the injured driver was taken to a hospital by an ambulance or paramedic unit. *** Mopeds, scooters, allterrain vehicles, other off-road vehicles, motorcycles of 1980 or earlier model years, and motorcycles with out-of-state registrations were excluded. The SWITRS and the police reports provided data about the driver (driver's license number, age, sex, and extent of injury); the vehicle (vehicle license number, identification number-when
recorded-make, and model year), and name and address of the registered owner.
Crash-Involved Dnvers: The license status of injured drivers was determined
from the California Department of Motor Vehicles (DMV) driver history file using the driver's license number recorded on the crash report. Drivers not licensed to operate motorcycles were classified as having a valid license for another class of vehicle, having a suspended or revoked license, or having no license at all.
***Personal communication, California High-
way Patrol, April 1990.
February 1991, Vol. 81, No. 2
Unlicensed operators included the following categories: no driver's license number recorded on the crash report, those whose license expired before the crash date, those whose license was first issued after the crash date, driver's license number beginning with "X" (indicating a DMV file with information on violations and crashes but no driver's license issued), and those with the DMV identification card only. License status was classified as unknown if the driver was licensed in another state or country, if the driver was listed on the crash report as having an instruction permit or a temporary license, or if no computer record could be located for the driver's license number written on the crash report. If the driver's license history contained no record of a crash on the date of interest and the driver's birth date was inconsistent with the age on the crash report, the driver's license history data were not used and license status was also considered to be unknown. Owners of Crash-Involved Motorcycles: In cases in which the crash-involved driver did not own the motorcycle, information on the license status of the owner was obtained. Because the owner's name and addresses-but not the owner's driver's license number-are on the crash report, it was necessary to match the name and address information on the crash report with name and address information on the California driver's license history file to identify the owners' driver's license number and obtain licensure information.
A comparison group composed of a random sample of 13,638 motorcycles, representing 4.5 percent of all registered motorcycles in California, was selected from the DMV vehicle registratior file as of November 1, 1986. Inclusion in this sample was restricted in the same way as for motorcycles involved in crashes. The chance of a motorcycle being included in the sample was proportional to the number of months in which it was validly registered in California during the study period. Once in the sample, motorcycles were assigned with equal probability to each of the 16 months in the study during which they were registered for use. This procedure resulted in a comparison sample that included every motorcycle that was registered during a month with equal probability for that month. The driver's license history for the owners of motorcycles in the comparison sample was obtained in the following way. The status of the license was determined for the reference month to which the motorcycle was assigned for comparison. Of the initial sample of 13,638 motorcycles, name and address for the registered owner were available for 12,481 of them (92 percent). The driver's license numberwas located for 8,669 of the 12,481 (69 percent). Of the 8,669, a driver's license history file was located for 8,648 owners (99.8 percent). Based on the vehicle identification number, 8,510 of the vehicles were found to be true motorcycles. Driver's license histories of owners were randomly discarded until all months had a sampling ratio of 2.56 controls per case, the ratio found in the sparsest month. The final comparison sample included 6,965 vehicle owners.
Resulls Licensure Information The information available for subgroups of motorcycle owners and drivers is provided in Table 1. Licensure information was available for 94 percent of crashinvolved drivers but for only 56 percent of owners of motorcycles in crashes who were not driving the motorcycle and for 63 percent of the comparison sample of owners of motorcycles not in crashes. Licensure Rates Table 1 also provides a summary of motorcycle licensure rates for the various groups of motorcycle owners and drivers. American Journal of Public Health 173
Kraus, et aL
Percent Liosneed
70 .------60 ..-..-.-----...-...-
..........
.. .. ..
. ...
Owners mot In orseaks 60 ..-
40
.
.
..--.
-
.-....--..-.--.
.---... .-
.--
..........................-----..-.
... .
-
.-......-...
......
Owners In oraehes .. .. .....~....... .
30t.
2 0 -
..
.. 10 .............................. -
0
16-17
..........................................................
.....
... . . .....
................
._
_
.
............................
............. . ..................................... .... . . . --1
................
I
I
p
p
18-19
20-24
26-29
30-39
%
40
Age
FIGURE 1-Percent of Validly Lcensed Motorcyclists: Owners of Motorcycles In Crashes vs. Owner of Motorcyces not In Crashes, by Age
Owners: Owners of motorcycles in crashes were less likely to have valid licenses than motorcycle owners not in crashes (42 percent vs. 57 percent, odds ratio [OR] = 0.53, 95 percent confidence interval [CI] = 0.48, 0.59). Owners of crashed motorcycles were younger than the comparison group of motorcycle owners: 44 percent were under age 25 compared with 22 percent of the comparison group (OR = 2.86, CI = 2.58, 3.18). Owner licensure rates in both groups increased with age until age 40; fewer owners age 40 and over were licensed than owners ages 30-39. Figure 1 shows that the younger age of owners of crashed motorcycles did not account for the relationship between owner licensure and crash involvement. At all ages, owners of crashed motorcycles were less likely to be validly licensed than owners not in crashes (OR = 0.60, CI = 0.54, 0.66). Owners of motorcycles in crashes who were operating the motorcycle were
174 American Journal of Public Health
also less likely to be validly licensed than motorcycle owners not in crashes (44 vs. 57 percent, OR = 0.59, CI = 0.53, 0.66). Drivers: Overall, 33 percent of crashinvolved drivers were validly licensed. Valid licensure was strongly associated with age. The lowest licensure rate was among those under age 20 (18 percent); the highest rate was among those age 40 and older (51 percent). Thirty-nine percent of the drivers were operating motorcycles they did not own, and they were less likely to be licensed than driver-owners (20 percent vs. 44 percent, OR = 0.31, CI = 0.26, 0.38). Driver-nonowners tended to be younger than driver-owners (63 percent were under age 25 compared with 47 percent of driver-owners; OR = 1.97, CI = 1.65, 2.34), but as shown in Figure 2, the differences in licensure rates between these two groups held, regardless of age (OR = 0.35, CI = 0.29, 0.43).
Among crash-involved drivers without valid licenses, 53 percent had a license to drive a passenger car but did not have a motorcycle endorsement, 31 percent did not have a license to drive any kind of motor vehicle, and 16 percent had sus-
pended or revoked licenses.
Owner-Driver Paius Table 2 displays the percentage of validly licensed driver-nonowners by age, motorcycle owner license status, and the relationship between the driver and the owner. Older owners are defined as those who are more than 10 years older than the driver. Overall, in 56 percent of the 517 pairs, neither driver-nonowner nor owner was validly licensed. Valid driver licensure increased with driver age and with having a licensed owner. When owners were licensed, 27 percent of the drivers held valid licenses. When owners were unlicensed, only 14 percent of the drivers were licensed.
FebnLaiy 1991, Vol. 81, No. 2
Motorcyde licensre, Ownership, and Injury Crash Involvement
Percent Licensed
60 80-..
--
.
_
_
_
.
.
Driver-Owners .......----------
_ __...........................
.
30.-
--
.
..............
_
20 .........
......
~~~~~~~~~Driver-Nonownersl r 10-.........................-
0
16-17
I
18-19
..... ....
-
...
....
I
25-29
20-24
30-39
>40
Age FIGURE 2-Percent of Validly Ucensed Motorcycists: Driver/Owners in Crashes vs. Drivers who do not own the Motorcycle
The data were analyzed using a loglinear model that included the three factors shown in Table 2 plus the interaction between motorcycle owner license status and the relationship between the drivernonowner and the motorcycle owner. A greater proportion of drivers were licensed to operate a motorcycle if they were older and if the owner was licensed. More drivers were licensed if the owner was at least 10 years older than the driver and had the same last name or address as the driver, and fewer drivers were licensed when the owner was within 10 years of the driver's age and had a different last name and address.
Diwussion The proportion of unlicensed injured motorcycle drivers (67 percent) identified in this study is extraordinarily high compared with the proportion of fatally injured motor vehicle drivers (11 percent) in the
February 1991, Vol. 81, No. 2
US Fatal Accident Reporting System (FARS).4 Our results also indicate that motorcycles owned by people without motorcycle licenses are more likely to be in crashes than motorcycles owned by people with valid motorcycle driving licenses. The results strengthen earlier, incomplete findings by Hurt and associates and FARS that most motorcyclists in crashes, especially young motorcyclists, are not validly licensed. In addition, those driving motorcycles they did not own were likely to be unlicensed, especially if the ownerwas also not licensed to operate a motorcycle. The results also show that driver age, the use of someone else's motorcycle, and borrowing from an unlicensed owner are independent factors affecting valid licensure. Among young motorcyclists who crashed on motorcycles that were owned by other young and unlicensed motorcyclists, virtually none was validly licensed.
Unavailable data may alter somewhat the percentages presented. Licensure data were available for most of the drivers, but the driver's license status of only about 60 percent of the owners of motorcycles crashed by another operator and the random sample of owners of motorcycles not in crashes was known. This occurred usually because the name and address of the owner could not be matched with a name and address on the driver's license file. This linkage can fail for various reasons, such as a change of address by the owner. It is not known whether owners who could not be traced had a different percentage of valid licensure than those successfully traced. Several countermeasures can be considered for reducing the crashes associated with invalidly licensed motorcycle owners and drivers. Requiring proof of valid licensure as a prerequisite for purchasing a motorcycle would reduce the extent towhich owners and drivers are not
American Journal of Public Health 175
Kmos, et al. 111111.1- diiiiii III
------------------------1. iiiiiiii li.-
...................
..................
...................
....
.................
..................
..........................
.......
................................
..............
.......................... R
...................
..........................
of the California Highway Patrol Commissioner, James E. Smith; Management Information Section (Sgt. John Bailey and Bev Christ); California Department of Motor Vehicles, Division of EDP Service (Neal Graham, Associate Data Processing Analyst); Drivers License Automation Development Unit (Rudy Modelo); and Research and Development Section (William Marsh). We also thank Steven Harrington and Ching-Sung Wu for computer-programming assistance.
.... ..........
References .......................
.........................
............................... ................. ................................
..............................
.... ...
........................................ ...............
..
properly licensed. Motorcycle driving by invalidly licensed people might be reduced by stepping up enforcement of licensure laws and/or providing more stringent penalties for lack of licensure. Penalties against the owners of motorcycles driven by invalidly licensed drivers could deter owners from allowing such people to operate their motorcycles. If applied, these measures could change the behavior of motorcycle owners and operators in one of two ways: these people can avoid sanctions either by obtamiing the proper license or by not driving. Measures that merely force licensure but do not change the amount of driving may have no effect on crashes. When ex-
176 American Journal of Public Health
isting licensure and training programs have been formally evaluated based on random assignment, the programs have not been shown to be effective in reducing crashes.t ff Thus, sanctions applied to unlicensed drivers and owners are more likely to be effective if they reduce driving than ifthey merely shift unlicensed driving to licensed driving. If the measures reduce exposure, they will reduce crashes, especially of young, novice, unlicensed drivers on borrowed bikes. O
Acknowledgments
1. Barry PZ: The role of inexperience in motorcycle crashes. J Safety Res 1970; 2:229239. 2. California Vehicle Code, Sections 12512.5 and 12804. Sacramento, CA: Department of Motor Vehicles, 1987. 3. California Highway Patrol: Collision Investigation Manual, Section 4.10.4. Sacramento, CA, May 1987; 4-57. 4. US Department of Transportation, National Highway Traffic Safety Administration: Fatal Accident Reporting System 1988. DOT HS 807 507. Washington, DC: US Govt Printing Office, December 1989.
tKelsey SL, Liddicoat C, and Ratz M: Licensing novice motorcyclists: A comparison of the traffic safety impact of California's standard test and the M.O.S.T. II (Motorcycle Operator Skill Test) administered at centralized testing offices. (CAL-DMV-RSS-86-106). Sacramento, CA: California Department of Motor Vehicles, 1986.
ttNew York State Department of Motor Vehicles: Motorcycle Rider Education Evaluation. Albany, NY: New York State Department of Motor Vehicles, 1988.
This work would not have been possible without the splendid cooperation ofthe Department
February 1991, Vol. 81, No. 2
-ewX-.,
lzw ;llKIl'-ll;--.-l;z.-X-H:.
Jess F. Kraus, PhD, Craig Anderson, DHSc, Paul Zador, PhD, Allan Wdliams, PhD, Shakeh Arzemanian, MPH, Weichang Li, MA, and Michael Salatka, MPH
Introdudtion In most states a special license is required to operate a motorcycle on public streets and highways. There is evidence, however, that many of the motorcycle drivers killed or seriously injured in crashes did not have a license to operate a motorcycle. Hurt and associates* reported in an unpublished document that 46 percent of 900 motorcycle drivers involved in crashes in Los Angeles in 1976-77 were not validly licensed. Data from the US Department of Transportation's Fatal Accident Reporting System (FARS)** show that about 43 percent of motorcyclists killed on public roads or highways in the United States did not hold a valid motorcycle operator's license. In both reports, however, there was no information given on licensure status of motorcyclists not involved in injury crashes. Neither of these data sets provides information on whether the injured were driving motorcycles they owned, nor do they indicate whether lack of licensure was associated with increased crash risk. Barry' noted 20 years ago that a substantial percentage of operators of motorcycles involved in injury crashes had "borrowed" the vehicle, but the report did not include information on whether the motorcyclists were licensed. The present study was designed to address the following questions: * Do motorcycles owned by people without motorcycle licenses have greater likelihood of crash involvement? * To what extent do motorcycle drivers in serious and fatal injury crashes have valid licenses? own the motorcycle they were driving?
* How does motorcycle licensure vary by whether the crash-involved driver owned the motorcycle ("driver-owner" vs. "driver-nonowner")? * How is motorcycle licensure affected by the relationship between crashinvolved driver-nonowners and owners, when other relevant factors are also controlled?
Methods A valid motorcycle license in California is a "class 4" license or, more frequently, a motorcycle endorsement to another class of license. Motorcycle licensure requires a written examination and driving test for two-wheeled vehicles. Motorcyclist training was not required for any drivers prior to 1988.2
Crash-Involved Motorcycles Motorcycle crashes that occurred between July 1, 1985 and October 31, 1986 *Hurt et al: Motorcycle accident cause factors and identification of countermeasures. Traffic Safety Center, University of Southern California, Los Angeles, 1981. **Buchanan L: Presentation at Transportation Research Board Meeting, Washington, DC, 1988.
Address reprint requests to Jess F. Kraus, PhD, Department of Epidemiology, School of Public Health, UCLA, Los Angeles, CA 90024-1772. Co-authors Anderson, Arzemanian, Li, and Salatka are also at UCLA. Dr Zador and Dr Williams are with the Insurance Institute for Highway Safety, 1005 N. Glebe Road, Arlington, VA 22201. This paper, submitted to the Journal February 28, 1990, was revised and accepted for publication June 14, 1990.
February 1991, Vol. 81, No. 2
Motorcyde Licensure, Ownership, and Injury Crash Involvement Owners of Motorcycles Not in Crashes (Comparison Group)
on a California road, street, or highway were identified using the California Highway Patrol (CHP) Statewide Integrated Traffic Records Systems (SWITRS) and the original police reports. Crashes analyzed were limited to those in which the motorcycle driver was fatally or severely injured. A severe injury was defined by the CHP3 as a cut or laceration of skin from which blood flows freely or saturates clothing, and also includes an extremity not in normal position, indicating fracture. In almost all cases, the injured driver was taken to a hospital by an ambulance or paramedic unit. *** Mopeds, scooters, allterrain vehicles, other off-road vehicles, motorcycles of 1980 or earlier model years, and motorcycles with out-of-state registrations were excluded. The SWITRS and the police reports provided data about the driver (driver's license number, age, sex, and extent of injury); the vehicle (vehicle license number, identification number-when
recorded-make, and model year), and name and address of the registered owner.
Crash-Involved Dnvers: The license status of injured drivers was determined
from the California Department of Motor Vehicles (DMV) driver history file using the driver's license number recorded on the crash report. Drivers not licensed to operate motorcycles were classified as having a valid license for another class of vehicle, having a suspended or revoked license, or having no license at all.
***Personal communication, California High-
way Patrol, April 1990.
February 1991, Vol. 81, No. 2
Unlicensed operators included the following categories: no driver's license number recorded on the crash report, those whose license expired before the crash date, those whose license was first issued after the crash date, driver's license number beginning with "X" (indicating a DMV file with information on violations and crashes but no driver's license issued), and those with the DMV identification card only. License status was classified as unknown if the driver was licensed in another state or country, if the driver was listed on the crash report as having an instruction permit or a temporary license, or if no computer record could be located for the driver's license number written on the crash report. If the driver's license history contained no record of a crash on the date of interest and the driver's birth date was inconsistent with the age on the crash report, the driver's license history data were not used and license status was also considered to be unknown. Owners of Crash-Involved Motorcycles: In cases in which the crash-involved driver did not own the motorcycle, information on the license status of the owner was obtained. Because the owner's name and addresses-but not the owner's driver's license number-are on the crash report, it was necessary to match the name and address information on the crash report with name and address information on the California driver's license history file to identify the owners' driver's license number and obtain licensure information.
A comparison group composed of a random sample of 13,638 motorcycles, representing 4.5 percent of all registered motorcycles in California, was selected from the DMV vehicle registratior file as of November 1, 1986. Inclusion in this sample was restricted in the same way as for motorcycles involved in crashes. The chance of a motorcycle being included in the sample was proportional to the number of months in which it was validly registered in California during the study period. Once in the sample, motorcycles were assigned with equal probability to each of the 16 months in the study during which they were registered for use. This procedure resulted in a comparison sample that included every motorcycle that was registered during a month with equal probability for that month. The driver's license history for the owners of motorcycles in the comparison sample was obtained in the following way. The status of the license was determined for the reference month to which the motorcycle was assigned for comparison. Of the initial sample of 13,638 motorcycles, name and address for the registered owner were available for 12,481 of them (92 percent). The driver's license numberwas located for 8,669 of the 12,481 (69 percent). Of the 8,669, a driver's license history file was located for 8,648 owners (99.8 percent). Based on the vehicle identification number, 8,510 of the vehicles were found to be true motorcycles. Driver's license histories of owners were randomly discarded until all months had a sampling ratio of 2.56 controls per case, the ratio found in the sparsest month. The final comparison sample included 6,965 vehicle owners.
Resulls Licensure Information The information available for subgroups of motorcycle owners and drivers is provided in Table 1. Licensure information was available for 94 percent of crashinvolved drivers but for only 56 percent of owners of motorcycles in crashes who were not driving the motorcycle and for 63 percent of the comparison sample of owners of motorcycles not in crashes. Licensure Rates Table 1 also provides a summary of motorcycle licensure rates for the various groups of motorcycle owners and drivers. American Journal of Public Health 173
Kraus, et aL
Percent Liosneed
70 .------60 ..-..-.-----...-...-
..........
.. .. ..
. ...
Owners mot In orseaks 60 ..-
40
.
.
..--.
-
.-....--..-.--.
.---... .-
.--
..........................-----..-.
... .
-
.-......-...
......
Owners In oraehes .. .. .....~....... .
30t.
2 0 -
..
.. 10 .............................. -
0
16-17
..........................................................
.....
... . . .....
................
._
_
.
............................
............. . ..................................... .... . . . --1
................
I
I
p
p
18-19
20-24
26-29
30-39
%
40
Age
FIGURE 1-Percent of Validly Lcensed Motorcyclists: Owners of Motorcycles In Crashes vs. Owner of Motorcyces not In Crashes, by Age
Owners: Owners of motorcycles in crashes were less likely to have valid licenses than motorcycle owners not in crashes (42 percent vs. 57 percent, odds ratio [OR] = 0.53, 95 percent confidence interval [CI] = 0.48, 0.59). Owners of crashed motorcycles were younger than the comparison group of motorcycle owners: 44 percent were under age 25 compared with 22 percent of the comparison group (OR = 2.86, CI = 2.58, 3.18). Owner licensure rates in both groups increased with age until age 40; fewer owners age 40 and over were licensed than owners ages 30-39. Figure 1 shows that the younger age of owners of crashed motorcycles did not account for the relationship between owner licensure and crash involvement. At all ages, owners of crashed motorcycles were less likely to be validly licensed than owners not in crashes (OR = 0.60, CI = 0.54, 0.66). Owners of motorcycles in crashes who were operating the motorcycle were
174 American Journal of Public Health
also less likely to be validly licensed than motorcycle owners not in crashes (44 vs. 57 percent, OR = 0.59, CI = 0.53, 0.66). Drivers: Overall, 33 percent of crashinvolved drivers were validly licensed. Valid licensure was strongly associated with age. The lowest licensure rate was among those under age 20 (18 percent); the highest rate was among those age 40 and older (51 percent). Thirty-nine percent of the drivers were operating motorcycles they did not own, and they were less likely to be licensed than driver-owners (20 percent vs. 44 percent, OR = 0.31, CI = 0.26, 0.38). Driver-nonowners tended to be younger than driver-owners (63 percent were under age 25 compared with 47 percent of driver-owners; OR = 1.97, CI = 1.65, 2.34), but as shown in Figure 2, the differences in licensure rates between these two groups held, regardless of age (OR = 0.35, CI = 0.29, 0.43).
Among crash-involved drivers without valid licenses, 53 percent had a license to drive a passenger car but did not have a motorcycle endorsement, 31 percent did not have a license to drive any kind of motor vehicle, and 16 percent had sus-
pended or revoked licenses.
Owner-Driver Paius Table 2 displays the percentage of validly licensed driver-nonowners by age, motorcycle owner license status, and the relationship between the driver and the owner. Older owners are defined as those who are more than 10 years older than the driver. Overall, in 56 percent of the 517 pairs, neither driver-nonowner nor owner was validly licensed. Valid driver licensure increased with driver age and with having a licensed owner. When owners were licensed, 27 percent of the drivers held valid licenses. When owners were unlicensed, only 14 percent of the drivers were licensed.
FebnLaiy 1991, Vol. 81, No. 2
Motorcyde licensre, Ownership, and Injury Crash Involvement
Percent Licensed
60 80-..
--
.
_
_
_
.
.
Driver-Owners .......----------
_ __...........................
.
30.-
--
.
..............
_
20 .........
......
~~~~~~~~~Driver-Nonownersl r 10-.........................-
0
16-17
I
18-19
..... ....
-
...
....
I
25-29
20-24
30-39
>40
Age FIGURE 2-Percent of Validly Ucensed Motorcycists: Driver/Owners in Crashes vs. Drivers who do not own the Motorcycle
The data were analyzed using a loglinear model that included the three factors shown in Table 2 plus the interaction between motorcycle owner license status and the relationship between the drivernonowner and the motorcycle owner. A greater proportion of drivers were licensed to operate a motorcycle if they were older and if the owner was licensed. More drivers were licensed if the owner was at least 10 years older than the driver and had the same last name or address as the driver, and fewer drivers were licensed when the owner was within 10 years of the driver's age and had a different last name and address.
Diwussion The proportion of unlicensed injured motorcycle drivers (67 percent) identified in this study is extraordinarily high compared with the proportion of fatally injured motor vehicle drivers (11 percent) in the
February 1991, Vol. 81, No. 2
US Fatal Accident Reporting System (FARS).4 Our results also indicate that motorcycles owned by people without motorcycle licenses are more likely to be in crashes than motorcycles owned by people with valid motorcycle driving licenses. The results strengthen earlier, incomplete findings by Hurt and associates and FARS that most motorcyclists in crashes, especially young motorcyclists, are not validly licensed. In addition, those driving motorcycles they did not own were likely to be unlicensed, especially if the ownerwas also not licensed to operate a motorcycle. The results also show that driver age, the use of someone else's motorcycle, and borrowing from an unlicensed owner are independent factors affecting valid licensure. Among young motorcyclists who crashed on motorcycles that were owned by other young and unlicensed motorcyclists, virtually none was validly licensed.
Unavailable data may alter somewhat the percentages presented. Licensure data were available for most of the drivers, but the driver's license status of only about 60 percent of the owners of motorcycles crashed by another operator and the random sample of owners of motorcycles not in crashes was known. This occurred usually because the name and address of the owner could not be matched with a name and address on the driver's license file. This linkage can fail for various reasons, such as a change of address by the owner. It is not known whether owners who could not be traced had a different percentage of valid licensure than those successfully traced. Several countermeasures can be considered for reducing the crashes associated with invalidly licensed motorcycle owners and drivers. Requiring proof of valid licensure as a prerequisite for purchasing a motorcycle would reduce the extent towhich owners and drivers are not
American Journal of Public Health 175
Kmos, et al. 111111.1- diiiiii III
------------------------1. iiiiiiii li.-
...................
..................
...................
....
.................
..................
..........................
.......
................................
..............
.......................... R
...................
..........................
of the California Highway Patrol Commissioner, James E. Smith; Management Information Section (Sgt. John Bailey and Bev Christ); California Department of Motor Vehicles, Division of EDP Service (Neal Graham, Associate Data Processing Analyst); Drivers License Automation Development Unit (Rudy Modelo); and Research and Development Section (William Marsh). We also thank Steven Harrington and Ching-Sung Wu for computer-programming assistance.
.... ..........
References .......................
.........................
............................... ................. ................................
..............................
.... ...
........................................ ...............
..
properly licensed. Motorcycle driving by invalidly licensed people might be reduced by stepping up enforcement of licensure laws and/or providing more stringent penalties for lack of licensure. Penalties against the owners of motorcycles driven by invalidly licensed drivers could deter owners from allowing such people to operate their motorcycles. If applied, these measures could change the behavior of motorcycle owners and operators in one of two ways: these people can avoid sanctions either by obtamiing the proper license or by not driving. Measures that merely force licensure but do not change the amount of driving may have no effect on crashes. When ex-
176 American Journal of Public Health
isting licensure and training programs have been formally evaluated based on random assignment, the programs have not been shown to be effective in reducing crashes.t ff Thus, sanctions applied to unlicensed drivers and owners are more likely to be effective if they reduce driving than ifthey merely shift unlicensed driving to licensed driving. If the measures reduce exposure, they will reduce crashes, especially of young, novice, unlicensed drivers on borrowed bikes. O
Acknowledgments
1. Barry PZ: The role of inexperience in motorcycle crashes. J Safety Res 1970; 2:229239. 2. California Vehicle Code, Sections 12512.5 and 12804. Sacramento, CA: Department of Motor Vehicles, 1987. 3. California Highway Patrol: Collision Investigation Manual, Section 4.10.4. Sacramento, CA, May 1987; 4-57. 4. US Department of Transportation, National Highway Traffic Safety Administration: Fatal Accident Reporting System 1988. DOT HS 807 507. Washington, DC: US Govt Printing Office, December 1989.
tKelsey SL, Liddicoat C, and Ratz M: Licensing novice motorcyclists: A comparison of the traffic safety impact of California's standard test and the M.O.S.T. II (Motorcycle Operator Skill Test) administered at centralized testing offices. (CAL-DMV-RSS-86-106). Sacramento, CA: California Department of Motor Vehicles, 1986.
ttNew York State Department of Motor Vehicles: Motorcycle Rider Education Evaluation. Albany, NY: New York State Department of Motor Vehicles, 1988.
This work would not have been possible without the splendid cooperation ofthe Department
February 1991, Vol. 81, No. 2
