439 studies were removed in examining the title and abstract among 675 guides, papers, and instructions extracted from databases and manual text search, and after removing repeated cases. Additionally, 150 studies were excluded from the full literature review, which ultimately, 24 documents were included in the study (one Australian study that has been divided into 9 studies by each state) (Figure 1).
General charactristics of studies
Studies included were 7 were papers and 17 instructions. The period of publication of the included studies was between 2003 and 2020 and the middle year of publication of the studies was 2016. The study was conducted in six countries, all of them were high-income countries, and Australia had the most studies (10 studies). Among the 24 included studies 16 studies did not distinguish between professional and non-professional drivers (Table 1: specifications related to measuring and improving driving skills in the elderly) (additional file2: general specifications of studies).
Baseline age to assessment fitness to drive in the elderly
Most studies (13 cases) did not mention the baseline age of elderly drivers. Among the studies that referred to the baseline age of elderly drivers, the highest frequency was 70 years old (4 studies). A study conducted in the USA explained that the baseline age differs from state to state, ranging from 65 to 80 years . According to the increase in life expectancy in Canada to over 80 years, the baseline age for renewing the driving license of the elderly has been considered 80 years in this country  (additional file 3: base ages for vision assessment, driving assessment and clinical assessment of elderly drivers in Australia by state).
Judgment items in assessment fitness to drive in the elderly
20 studies referred to physical items, 10 studies referred to driving assessment and history, 5 studies to psychological items, and 4 studies to other judgment items on driving fitness in the elderly among 24 studies included. Judgment items on elderly driving fitness were classified into 5 groups (Figuer 2).
Vision test was the main item of judgment about the eligibility of elderly drivers, as 75% of the studies mentioned it. Most USA states have a vision test, regardless of age at the time of renewing the driving license, while the vision test is compulsory only for older drivers in other states . In the USA, the AARP/American Association of Retired Person self-assessment handbook is prepared for the elderly, which is a combination of hand and foot tests as well as self-administrate tests such as the Trail Making Test (TMT). This tool enables the possibility of self-assessment of reaction time, attention, vision, near miss experiences, and driving behavior. The new modified tool called Driving Decision Workbook also provides medical status and medication use, as well as more details on driving issues in addition to assessing vision, cognition, reaction time, accidents, and traffic conditions .
Policies to renewal and suspend driving licenses for the elderly
8 studies in the United States, Ireland, Australia, New Zealand, and Canada referred to the process of renewing an older driver's license among the 24 included studies [8, 21, 30, 32-36]. Two studies referred to complete the driver's license renewal application form as the first stage in the renewal process [32, 34]. Two studies [21, 36] referred to complete the self-declaration (self-assessment), and 4 studies [8, 21, 32, 33] referred to the medical assessment and receiving a medical certificate. Furthermore, 3 studies [8, 32, 36] referred to the examination of elderly driving before the renewal of the license by driving assessment specialists, and also one study  referred to the examination of the elderly's driving history as part of the process of renewing the driving license. 3 studies mentioned that the patient referred to a driving rehabilitation specialist if necessary [8, 32, 33]. If the patient has a mild to moderate medical condition, the physician should refer the person to a driving rehabilitation specialist for rehabilitation and return to safe driving. There is a need to follow and monitor the elderly condition to prevent and manage medical conditions that cause sudden disqualification in the elderly, as well as to prevent psychological damages, but only one study referred to follow the elderly conditions after renewing the license .
Different countries have various processes for screening and identifying unsafe older drivers at the time of renewing their licenses. For example, there is a three-stage process for identifying, assessing, referring, or revoking in the United States. At the stage of identifying all elderly drivers in terms of medical risks, medicine risks, drug and alcohol abuse, acute events and driving concerns, and if a disorder is distinguished, the person is referred to the CDRS(Certified Driver Rehabilitation Specialists) or DRS(Driver Rehabilitation Specialists) in the presence of mild or moderate disorders for further assessment of vision, neuromuscular function, and cognitive impairments , and the driver's license is canceled and the person is restricted from driving in the presence of severe, uncontrollable and irreversible disorders . In Australia, drivers in most states are obligated to offer a medical self-report on driving fitness when renewing or obtaining a license. This information may be directed to a medical assessment or nonrenewing the license. Each state has specific requirements for a medical or driving test before renewing the license according to the age and type of vehicle .
Face-to-face renewal with 5 cases [19, 21, 33, 36, 37] is the most prevalent method of renewing the license in the elderly among the methods to renewing the license in the elderly, and the postal [19, 34, 37] and Online methods [34, 36] with 3 and 2, respectively, are other methods of renewing the license in the elderly. All three methods are common in some countries; elderly people with diseases must renewing their driver's license in person and after a clinical assessment (Table 2: driver license renewal method in the elderly and its validity period in included studies).
However, if the person does not have a specific illness, he/she can renewing his / her license in absentia (by mail or online)  .
Among the studies included, 18 studies did not mention the validity period of the elderly driver's license, the validity period was 4 years in two studies, 2 years in one study, 3 years in one study, the average validity period of the license in the various states was 4.4 and 5 years in a study at the ages of 75 and 80 and then two years  .
5 studies referred to the policies for getting a license renewal fee and other related costs such as driving test fees [21, 30, 33, 34, 38]. In the United States, driving assessment are not frequently covered by insurance, and patients have to pay out-of-pocket for rehabilitation services from $ 200 to $ 400 for assessment and $ 100 per hour for rehabilitation  . In Northern Ireland, if you apply for a renewal of your license more than two months before the expiration of your current license, you will not be charged any fees for renewing your expired license  .
3 studies referred to time and manner of reminding to renew the driver's license in the elderly [34, 36, 37] . In Northern Ireland, about two months before the expiration of the current license, the DVA sends an extension notice to the elderly driver (DLR1)  .
7 studies referred to various types of driving suspension policies in the elderly [8, 21, 33-37]. In Australia, it is advised to the person to avoid driving for a period of time depending on the type and severity of the disease or medical condition, for example, if a person experiences anesthesia, depending on the opinion of experts, he/she should avoid driving until their physical and mental condition is not compatible with safe driving. In the case of more moderate surgeries or the use of short-term anesthetics, the patient may be able to drive after a night's sleep. The patient may not be safe to drive for at least 24 hours in the case of longer surgeries with general anesthesia. Medical professionals should determine the period without driving after surgery, and a practical assessment of the individual driving may be useful in determining driving eligibility . In Northern Ireland, if an elderly driver suffers from cataracts, but his/her vision is adequate for driving, she/he should avoid driving at night and also in intense sunlight .
Trustees and executors of the process of renewing the driver's license in the elderly
7 studies introduced a general practitioner, 7 studies a specialist, 3 studies a driving assessor, and 3 ones referred to the drivers themselves as executors and participants among the 24 studies in the process of renewing a driver's license in the elderly (Figure 3).
4 studies referred to the policymaker of the process of renewing the driver's license in the elderly [19, 21, 34, 37]. In the United States, several jurisdictions in the United States and abroad attempt to remove the risks related to elderly driving through laws and policies related to driving and renewing the licenses . In Northern Ireland, the DVA organization regulates the process to renew the license for the elderly . In Australia, Austroad and the National Transport Commission (NTC) organizations are responsible for policy-making . In another study, the Department of Planning, Transport, and Infrastructure has been identified as a major policymaker in Australia .
Empowerment policies for elderly drivers
13 studies referred to the road tests as part of the driver's license renewal process among the 24 included studies. 5 studies consider it necessary to provide safe driving tips for empowering older drivers [8, 31, 34, 36, 38]. Also, 5 studies referred to classroom training as a tool for empowering the elderly driver [9, 30, 31, 36, 37] (Table 3: types of empowerment policies in included studies).
Supportive policies for elderly deprived of driving
9 studies included supportive policies for the elderly deprived of driving [8, 9, 21, 31, 33, 34, 36-38]. The main supportive policy was to introduce alternative transportation to the elderly, which was mentioned in 7 studies [8, 9, 33, 34, 36-38]. One of the main reasons for the requirement of the elderly has been named to drive, prepare food and purchase items, in this regard, in the UK, the elderly can pay for a fixed monthly payment and use the (All-you-can-eat) service for in absentia food ordering. Transportation in London for the elderly, there are specific discounts on rail transport on the oyster card. It is also suggested to encourage the pilot implementation of alternative transportation options such as the use of self-driving vehicles by the government . In Australia, a card is issued to an elderly person who is deprived of driving that he or she can use public transport for free at certain times using that card . North East Driver Mobility organization has been created in the UK in order to help people maintain their independence as a driver or passenger. This organization provides the following services:
- Assess driving ability.
- Counseling on vehicle compatibility.
- Counseling on how to get in and out of the vehicle and maintain a wheelchair.
- Specialized driving instruction.
- Informing and counseling on alternatives to car use, such as transportation services in the community.
Treatment, prevention, maintaining and improving health policies
16 studies referred to the policies to treatment, prevent, maintain, and improve the health of older drivers through screening, clinical assessment, and general performance assessment. In different Australian states, for example, there are special conditions for clinical assessmentfor various types of driver's licenses, that older drivers after a certain age must pass a clinical assessmentat pre-determined intervals to renew their license . In the UK, an elderly person may be contested if he/she has a specific medical condition that was not reported and may affect a person's safe driving and cause a vehicle accident. In this case, insurance may even refuse to cover the elderly person . In the United States, physicians have advised that physicians help their elderly patients maintain safe mobility in two methods. Physicians provide effective treatment and preventive health care and play a role in determining the elderly's capacity to drive securely. In many cases, physicians can keep patients on the road for longer period by identifying and managing diseases such as cataracts and arthritis or by stopping tranquilize medication. Improving cardiovascular and bone health can also reduce serious injuries and increase recovery in an accident . A practical driver assessment may indicate a person's necessary to participate in a rehabilitation or retraining program in Australia. This course is set based on practical driver assessment results and may use for vehicle correction training or instruction to improve driving confidence. At the end of the course, the patient's driving skills may be reassessment, and a report sent to the driving license authority .
Due to the limited number of words in the main text of the article, some of the findings of the study in the form of mega data are presented in additional file 4.