as the older adult population grows , the number of older drivers also increases . these 
 drivers tend to drastically reduce the amount that they drive , since many are retired and 
 have a limited range of everyday and economic activities . additionally , drivers abilities 
 are affected by their normal aging as well as geriatric diseases , such as declines in visual 
 function , attention and processing speed , physical movement , and visual perception , along 
 with cognitive disabilities , diabetes mellitus and cardiovascular diseases1 .
therefore , it is necessary to be able to 
 accurately assess driving abilities and to retrain older individuals in order to reduce the 
 risk of motor vehicle collisions .
previous studies have introduced various measures for 
 examining and predicting driving performance declines and the accident risk aging adults for 
 use in research and clinical settings2 . in 
 gerontology
, some researchers have recognized the diversity of older adults and classified 
 them into three sub - groups : young - old ( 6574 ) , middle - old ( 7584 ) , and oldest - old ( 85 and 
 above)3 .
this study evaluated two 
 self - report questionnaires assessing the driving performance of young - old self - driving 
 adults : the safe driving behavior measure ( sdbm ) and the driving habits questionnaire 
 ( dhq)4 , 5 .
the purpose of this study was to investigate the accuracy of the 
 sdbm and dhq in identifying the history of collisions in community - dwelling young - old 
 self - driving adults .
a total of 45 community - dwelling young old self - driving adults , recruited from three senior 
 community centers , participated in this study .
this study was carried out in accordance with the 
 international ethical guidelines and the declaration of helsinki and was approved by the 
 local institutional review board of chosun university .
the inclusion criteria were as follows : age between 65 to 74  years , valid 
 driver s license , driving at the time of recruitment , cognitive ability to complete the sdbm 
 and the dhq , no missing limbs or major psychiatric diagnosis , and absence of neurological 
 deficits or severe orthopeadic diseases that might have impaired driving skills . 

table 1table 1.demographic profile and driving history of the participants ( n=45)variablesparticipantsgender ( male / female)34 ( 75.6%)/11 ( 24.4%)age ( years)68.36  3.18*height ( cm)166.76  6.95weight ( kg)66.33  7.58accident history ( yes / no)26 ( 57.8%)/19 ( 42.2%)driving exposure ( months)269.80  102.01mini - mental state examination ( scores)28.80  1.29*mean  standard deviation displays the clinical and demographic characteristics of the participants , 
 including gender , age , height , weight , and driving exposure . * mean  standard deviation all the participants completed the sdbm and the dhq . the sdbm is a self - report 
 questionnaire of safe driving behaviors that assesses the physical and cognitive aspects of 
 driving such as car controls or features , responses to physical and social factors , and 
 responses to environmental factors .
the 68 items are divided into three domains : 
 person - vehicle ( 11 items ) , person - environment ( 42 items ) , and person - vehicle - environment ( 15 
 items ) .
responses are made using a 5-point likert scale ranging from 1 ( can not do ) to 5 ( not 
 difficult ) , resulting in a total possible score of 340 points .
previous studies have 
 demonstrated the good validity and reliability of this instrument4 , 6 .
its counterpart , 
 the dhq is interviewer - administered , and consists of 34 items grouped into six domains , of : 
 current driving status and miscellaneous issues ( 10 items ) , driving exposure ( 4 items ) , 
 dependence on other drivers ( 2 items ) , driving difficulty ( 8 items ) , self - reported crashes 
 and citations ( 4 items ) , and driving space ( 5 items ) .
options for rating each item range 
 from 1 ( i drive ) to 3 ( this person drives ) , or from 1 ( so difficult i no longer drive in 
 that situation ) to 5 ( no difficulty ) so that the domain is scored on a 100-point scale . like 
 the sdbm
this study focused on only three domains of the dhq : driving 
 difficulty , self - reported crashes and citations , and driving space in order to obtain data 
 on the three domains in relation to traffic accidents .
descriptive statistics were used to analyze the demographic characteristics and driving 
 habits , such as current driving status and miscellaneous issues , and driving exposure of the 
 participants . to determine the cut - off values for the sdbm and the dhq , this study used the 
 receiver operating characteristic ( roc ) curve , and the area under the curve ( auc ) .
the auc 
 indicates the probability that young - old self - driving adults who have had collisions 
 experience will be correctly identified .
multivariate logistic regression analysis was 
 employed to identify the predictors of the history of accident in community - dwelling 
 young - old self - drivers .
analysis was performed with the aid of pasw version 18.0 for windows 
 ( spss inc . ,
this study examined 45 licensed drivers ( 34 males and 11 females ) with a mean age of 
 68.36  years , a mean height of 166.76  cm , and a mean body weight of 66.33  kg .
the mean duration of driving 
 experience was 269.80 months , and the mean mmse score was 28.8 ( table 1 ) .
the cut - off value , auc , sensitivity , and specificity of 
 the sdbm and dhq of community - dwelling young - old self - drivers were examined .
the sdbm , 
 cut - off values were found for the person - vehicle domain ( 53.5 ) , person - environment domain 
 ( 186.5 ) , person - vehicle - environment domain ( 52.5 ) . the cut - off values the dhq were 84.3 for 
 difficulty , 0.5 for accidents and citations , and 3.5 for driving space .
the auc values for 
 the person - vehicle domain , person - environment domain , and person - vehicle - environment domain 
 of the sdbm were 0.501 , 0.517 , and 0.549 respectively , and 0.593 , 0.616 , and 0.669 
 respectively .
the sensitivity was 0.538 for all three domains of the sdbm , while for the 
 dhq , the values for difficulty , crash and citations , and driving space were 0.577 , 0.423 , 
 and 0.615 , respectively , for the dhq .
the specificities of in the person - vehicle domain , 
 person - environment domain , and person - vehicle - environment domain of the sdbm were 0.474 , 
 0.526 , and 0.421 , respectively .
for the dhq , difficulty , crash and citations , and driving 
 space had values of 0.526 , 0.211 , and 0.421 , respectively ( table 2table 2.sensitivity and specificity of the sdbm and dhq of community - dwelling young - old 
 self - drivers ( n=45)variablecut - off valuearea under the curvesensitivity ( % ) specificity ( % ) sdbmpv53.5000.5010.5380.474pe186.5000.5170.5380.526pve52.5000.5490.5380.421dhqdifficulty84.3250.5930.5770.526crash and citations0.5000.6160.4230.211driving space3.5000.6690.6150.421dhq : driving habits questionnaire ; pv : person - vehicle domain ; pe : person - environment 
 domain , pve : person - vehicle - environment domain ; sdbm : safe driving behavior 
 measure ) .
according to multivariate regression analysis , the sdbm and dhq were not 
 significant predictors of collision history of community - dwelling young - old self - drivers . 

none of the three domains of the sdbm ( person - vehicle , person - environment , and 
 person - vehicle - environment ) significantly predicted collision history , and the three domains 
 of the dhq ( difficulty , crash and citations , and driving space ) were also not significant 
 predictors of collision history ( table 
 3table 3.multiple regression analysis of history of collisions and various driving 
 elements ( n=45)variablebsebetatpsdbmpv0.0390.0450.2330.8640.393pe0.0010.0100.0320.0700.945pve0.0050.0140.1160.3850.703dhqdifficulty0.0060.0120.1040.4970.622crash and citations0.1350.0800.2481.6960.098driving space0.1110.0580.3311.9140.063constant1.4741.6780.8780.385r*2=0.098dhq : driving habits questionnaire ; pv : person - vehicle domain ; pe : person - environment 
 domain , pve : person - vehicle - environment domain ; sdbm : safe driving behavior 
 measure ) .
dhq : driving habits questionnaire ; pv : person - vehicle domain ; pe : person - environment 
 domain , pve : person - vehicle - environment domain ; sdbm : safe driving behavior 
 measure dhq : driving habits questionnaire ; pv : person - vehicle domain ; pe : person - environment 
 domain , pve : person - vehicle - environment domain ; sdbm : safe driving behavior 
 measure
this study investigated the accuracy of the sdbm and dhq in identifying the automobile 
 accident history of community - dwelling young - old self - driving adults .
first , the auc was the greatest for the driving space of the 
 dhq , and the lowest for the person - vehicle domain of the sdbm .
second , overall the auc was 
 higher for the dhq than for the sdbm . finally , neither the sdbm or dhq were well - explained 
 predictors of collision history .
traffic accident - related injuries of the elderly are steadily increasing , and are becoming 
 a major social problem in post - industrial societies as the older population grows . 

therefore , screening for problematic driving behaviours of risk of older self - driving adults 
 is vital .
previous researchers have studied screening tests for risk of traffic collisions 
 in older drivers2 , 7 .
however , it is insufficient to base screening of driving abilities 
 or the risk of traffic collisions on sub - groups of age , as older adults vary in terms of 
 their physical and cognitive abilities . therefore , this study evaluated two major 
 measurement tools , the sdbm and the dhq .
previous studies have identified relationships 
 between aging - related conditions ( visual impairment , cognitive impairment , or motor 
 impairment ) and problematic traffic collisions5 , 8 , 9 . 

they reported that 
 older drivers with cataract experience a restriction in their driving mobility and a 
 decrease in their safety on the road5 . 

reported that the prospective follow - up of cohort of older drivers , 
 including both prospective collision records and identification of at - fault status , would 
 help to clarify the relationship between vision , cognition and motor or somatosensory skills 
 and fitness to drive8 .
however , this study 
 only included normal aging young - old self - driving adults .
they reported the sdbm has relevance 
 as a self - report instrument for assessing older drivers6 .
the results of the current study suggest that the sdbm and dhq can 
 predict driving - related collision history based on the auc values . however , the sdbm and dhq 
 were not accurate screening tests for the traffic collision history of young - old 
 self - driving adults
. this may be due to the limitation created by the relatively small 
 sample size of the young - old self - driving adults .
this study also had a cross - sectional 
 design and only young - old adults were studied .
future studies will be needed using larger 
 samples of young - old self - driving adults , as well as investigations of other sub - groups of 
 older adult drivers such as middle - old and the oldest adults .
 [ purpose ] to evaluate the sensitivity and specificity of the safe driving behavior 
 measure and the driving habits questionnaire in community - dwelling older self - drivers . 
 
 [ subjects and methods ] forty - five older participated in this study , to measure the safe 
 driving behavior measure and the driving habits questionnaire . sensitivity and specificity 
 were calculated along with cut - off values and overall accuracy of each measure as 
 determined by the participants operating characteristic curve and the area under the 
 curve . 
 multivariate logistic regression analysis was employed to identify predictors of 
 driving abilities . 
 [ results ] the sensitivities were 0.538 for safe driving behavior 
 measure , and 0.577 , 0.423 , and 0.615 for the difficulty , crash and citations , and driving 
 space on domains of the driving habits questionnaire , respectively . 
 the specificities of 
 the person - vehicle domain , person - environment domain , and person - vehicle - environment 
 domain of the safe driving behavior measure were 0.474 , 0.526 , and 0.421 , respectively , 
 while the driving habits questionnaire domains , the specificities of difficulty , crash and 
 citations , and driving space were 0.526 , 0.211 , and 0.421 , respectively . 
 [ conclusion ] the 
 results of this study suggest that factors related to the accident history of older 
 self - drivers were not well - explained , although the safe driving behavior measure and 
 driving habits questionnaire domains have the potential to determine driving - related 
 accident history . 
INTRODUCTION
SUBJECTS AND METHODS
RESULTS
DISCUSSION