All posts by cs-drivingsimulator

Can a simulator be used in driving tests?

In a driving test (also known as a driving exam) a person’s ability to drive a motor vehicle is tested. It is required to pass the test in order to obtain a driver’s licence. Usually, a driving test is separated into two parts: a road test, to assess driving ability, and a theory test, to test the knowledge of traffic rules and regulations.

The theory test usually is standardized and the same for all people who apply for the test. This makes the test fair. The situation for the road tests is totally different, however. In some countries the road test is restricted to testing the ability to control the vehicle. This concerns a maneuverability test that consists of driving through a set of traffic cones, reversing around a corner and making emergency stops. In other countries, the test consists of driving in traffic in various situations. The situations to which the student is exposed can differ widely. Some students perform the test in a complex urban traffic environment, while others enter and exit a highway a few times. Also, the interrater reliability is often very low, meaning that some examiners are more strict than others. This situation can make passing a road test look like a lottery.

It is often questionable whether the road test really tests the ability to drive a vehicle. Driving a vehicle entails much more than simple being able to control the vehicle. You have to be able to drive safe as well. You have to be able to anticipate on potentially dangerous situations, recognize road signs and know how to apply the rules of the road.

With a car driving simulator, driving tests can be made more fair. You can use a driving simulator to give every person the same test. This should preferably be a standardized test in which all relevant situations are included. Also, the problem of inter-examiner reliability is solved because the simulator software will rate driving behaviour consistently and apply the same norms for all students.

It will probably be a long way before driving simulators are used to test driving ability and replace the current road tests, but I think it will be a big step forward in terms of fairness and quality.

Differences in quality of driving schools

There are hugh differences in quality of driving schools. It is difficult to pinpoint exactly which factors determine whether a driving school is good or bad. There has been a lot research into factors that determine the quality of driver training, and the most consistent finding is that the amount of practice in relevant driving tasks is a very important factor. Lack of driving experience is probably the most important reason why young drivers fail for their driving exams or are overrepresented in the accident statistics. This would suggest that driving schools with an excellent track record generate more driving experience in their students, although this has not been investigated properly. This finding suggests that it is generally not a very good idea to apply for courses that promise passing the exam within only one week (crash courses). It also suggests that a learner permit where young drivers are supervised by an experienced driver and have to practice a lot while they are only allowed to drive in favourable circumstances (for example only during daylight) is probably a good idea. It has never been proved that supervision by professional instructors results in better drivers or higher pass rates at exams, compared to supervision by parents. All in all, extensive practive before the driver exam is taken appears to be the most important factor.

But it is clear that quality of the driving school is an important factor that affects the choice of a driving school by a learner driver. In most countries it is difficult for a customer to find out which driving school is the best. In the Netherlands, around 7750 driving schools were registered in 2012. All driving instructors have to be licenced and all have followed extensive training to become a registered instructor. In order to apply for your driving test, on average 40 lessons (one hour per lesson) are required in a learner car on public roads. The instructor determines when the learner driver drives good enough to have a good chance to pass for the exam. Still, year after year the average pass ratio for the driver test (first time) is 50%.

In the Netherlands the pass ratios of driving schools are publicly available via the website of the examination institute (CBR). These numbers are available to the public and are used by learner drivers to choose a driving school. A number of driving schools have consistent high scores while other driving school consistently perform poorly on pass ratio. What is a good driving school is a matter of definition ofcourse, but lets define a good driving school as a driving school where more than 75% of all students pass the first time they do the driving test. Over a large sample of driving schools, around 12,5% of all driving schools can be qualified as ‘good’, according to this definition. If we define a poor driving school as one where only 25% of all students pass for their exam the first time, then around 17,5% of all driving schools can be considered ‘poor’. 70% of all driving schools are then ‘average’.

The ‘good’ driving schools generally attract a lot of learner drivers. They do well economically, while the ‘poor’ driving schools struggle to survive, in general, in this very competitive market. Ofcourse there will always be a normal distribution of pass ratios where there will be relatively good and relative poor driving schools, but a pass percentage lower than 25% is low according to Dutch standards, where a pass ratio of 50% is considered ‘normal’. These driving schools can benefit strongly by using a car simulator to increase the level of practice and task automation in their students. This increases the quality of driver training for these driving schools because the simulator curriculum promotes task automation and extensive practive in relevant driving tasks. It is expected that this will increase the pass ratio and thus attract more customers.

Driving simulator applications

Car driving simulators are used for various purposes. The first thing that comes to mind when thinking about driving simulators is driver training. Most simulators are used for initial driver training in driving schools. See for more information an article about driving schools and one about the suitability of a driving simulator for driver tests. Other driving training applications are:

  • simulators for police training. Police training on public roads is often difficult because of regulations concerning the use of optical and sound signals (siren and flash light). Simulators can be very useful then because they allow policemen to practice driving with police siren. Other drivers often respond unexpectedly when a policecar approaches fast and with sound signals.
  • simulators for emergency services. Ambulance and fire engine drivers can also practice in a simulator in the use of optical and sound signals. A simulator offers excellent opportunities to practice driving in traffic and apply the rules for ‘priority vehicles’, while learning how to cope with other traffic.
  • training of hazard perception. Inexperienced drivers are often deficient in their recognition of hazards. A simulator can offer special training scenarios of unexpected situations that don’t occur often in the real world.

Apart from driver training, other driving simulator applications are:


Research simulator applications

Research driving simulators are used by research institutes, universities and car manufacturers. The typical advantages of using research simulators over real cars in the real world are:

  • Control over the environment and experimental conditions. If you want to do research in a real vehicle on public roads, two drives will never be the same. Weather, lighting, and traffic conditions always vary which will introduce a lot of uncontrolled measurement error in any experimental design. Also, in a driving simulator experimental conditions can be specified exactly, while this often is impossible in the real world.
  • Ease of measurement and data analysis. Ofcourse vehicles can be equipped with data measurement equipment (instrumented vehicle), but the ease of measurement in a simulator is unprecedented. Just specify the data you want to sample and the data sampling frequency and you are ready to go. Also, a lot if data if often difficult to measure in the real world, while in a simulator all data are often internally available (for example, time to intersection of vehicles approaching the intersection). This not only reduces costs tremendously, it also enabled experiments that are impossible to perform otherwise. Since the use of research simulators in traffic psychology, research into driving behaviour and the accumulation of knowledge has strongly increased,
  • Ethical considerations. Often it is undesirable to do research on the road because of ethical condiderations. Studies on the effects of alcohol and various drugs (sleeping pills, amphetamine etc) and of sleeping deprivation and fatigue are often better done in a simulator because of safety considerations.

Although the market for driver training is larger than for driver behaviour research, research simulators are used for a number of different purposes:

  • Human factors studies. An important use of research simulators is in human factor studies. This involves studies on the relation between man and machine. Studies on workload, the use of secondary tasks, the effects of presentation mode of information on driving performance, the effects of equipment (for example smart phones) on distraction etc, all are mostly done in simulators.
  • Effects of road infrastructure. When a road is designed the effects of road layout on driving behaviour can be studied in a simulator. Also, the effects of lighting conditions (streetlights) and road signs can be studies easily.
  • Driver behaviour modeling. At universities, the car driving task is often considered as a convenient task to study different factors of human behaviour. This concerns questions such as: What information do people use in their car following behaviour and how is choice of headway related to risk taking ?
  • Driver performance and impairment. The effects of alcohol and drugs on driver performance is studied in research simulators. Also the effects of prolonged driving and other factors that result in driver impairment are often studied in simulators.
  • Vehicle design. In the car industry, research simulators are used to study the effects of design decisions of driver behaviour. This usually requires very advanced engine and vehicle models, which makes these simulator usually expensive.


Driving under the influence and driving impairment

Drinking while driving (DUI) is still one of the main factors in accident causation. For an overview of drunk driving statistics in the US, click here. This is especially the case with young (male) drivers who combine the following risk factors that interact into severely increased accident risk and road fatalities in this group:

  • Inexperience. Young drivers are typically inexperienced drivers. That implies that driving still requires a lot of controlled attention, while in experienced drivers driving skills has become ‘automatic’ to a much higher degree. Skills that require controlled attention deteriorate much easier under the effects of factors such as intoxication (by alcohol and drugs) and fatigue. In several studies it has been shown that driving performance is more strongly affected by alcohol in young drivers compared to drivers with more driving experience. This is an important factor that results in more road fatalities in young drivers as a result of DUI.
  • Overestimation of skills and increased risk taking. Young (male) drivers overestimate their driving skills to a higher degree than other groups. While it is true that young drivers are characterized by faster responses and smaller reaction times, it is also true that reaction time is hardly a factor in accident causation. This has been clearly demonstrated in a lot of scientific research. People with faster responses often tend to take more risk by driving faster and choosing smaller headways to the lead vehicle. Young drivers usually take more risk and are poorer at estimating the effects of various factors on driving behaviour. This results in poorer anticipation and preview, insufficient increase of headway when the road becomes slippery, insufficient reduction of speed with an upcoming road curve, etc. Because they overestimate their skills, they tend to think they can overcome the negative effects of alcohol on driving performance by concentrating better, which is an obvious error in judgement.
  • Negative effects of alcohol on performance.
    • Alcohol affects motor skills resulting in increased reaction time and poorer steering control.
    • It also results in blurred vision. This makes detection of hazards even more difficult.
    • A typical effect of alcohol is that people get overconfident and they tend to overestimate their skills even more. This interacts with the overestimation of skill level that young (male) drivers already have.
    • From a traffic safety point of view, the most detrimental effect of alcohol is that people are often unaware of the performance deteriorations that are caused by alcohol. Because they are unaware of the negative effects, they don’t compensate their behaviour by driving slower of by anticipating better or taking a longer preview.

Because of these effects of alcohol on a group of drivers that is already more at risk, a car simulator is an excellent instrument to make young drivers become more aware of the effects of alcohol on their driving behaviour. When young drivers have really convincingly been demonstrated the effects of DUI on driving performance, they hopefully will think twice before drinking when they have to drive a car. To read more about the accident risk of young drivers, click here… To read more about the effects of alcohol on driving performance, click here….


Distracted driving simulator

Distracted driving is, next to DUI (driving under the influence), one of the main causes of car driving accidents. Distracted driving is the act of driving while engaged in other activities—such as looking after children, texting, talking on the phone or to a passenger, eating, or reading—that take the driver’s attention away from the road. All distractions compromise the safety of the driver, passengers, bystanders and those in other vehicles (definition from Wikipedia). Distracted driving is now considered as an epidemic: only in the US, in 2012 more than 3000 were killed in distracted driving crashes.

Driving a vehicle requires a considerable amount of attention. This is expecially so for young, inexperienced, drivers, who still need controlled attention while driving a car. Sharing their limited attentional resources with other tasks, such as texting or using a cell phone, goes at the expense of driving performance. Expecially when the eyes are taken off the road for more than 3 seconds will result in severly increased accident risk.

Young drivers typically overestimate their driving skils and their ‘multitasking’ ability. They often think they can do two things simultaneously: driving and texting. However, multitasking is only possible when both tasks don’t require controlled attentional resources, such as eating while walking. Texting definitely requires attentional resources and driving a car most definitely requires controlled attention for young drivers. This is the reason that distraction affects young drivers stronger compared to experienced drivers.

In order to make young drivers more aware of the effects of distracted driving on accident risk, a test drive in a driving simulator can be a convincing eye opener.

Treatment of fear of driving in a driving simulator

Driving phobia or excessive fear of driving refers to people who are so afraid to drive a car, that they avoid to drive a car. These people have obtained their drivers licence at some time. This may impact their lives severely and reduces their mobility. In the Netherlands between 800.000 and 1.000.000 people suffer from some form of fear of driving or driving phobia. Driving in a simulator can help to overcome fear of driving or driving phobia.

Methods and techniques based on Virtual Reality are applied to treat fear effectively, for example hosophobia, fear of spiders, etc., and they have proved to work. The advantage of simulators, and virtual reality in general, consists of the opportunities it provides to practice in a safe environment while the stimuli that evoke the fear response are presented in a controlled way. People are exposed to the fear-inducing stimuli, a technique also referred to as exposure therapy. This is probably the most effective technique from behavioural therapy to treat specific fears, such as driving phobia. Driving in a simulator will initially be frightening for people with fear of driving, but after some time of driving, fear will typically reduce.

The training has to have the following characteristics to be effective:

  • Driving in the simulator must be realistic.
  • The most frightening situations must be trained, for example driving on a highway with high traffic density.
  • People with driving experience and an age above 30 may be susceptible to simulator sickness. The simulations must be made such that the risk of simulator sickness is small.
  • The simulations must be long enough. If the session is too short and stops while fear has not been reduced, then the session may be counterproductive.


Clinical applications in a driving simulator

Car driving simulators are particularly known for their use in driver training, police training, and also for their application in DUI simulation and demonstrating the effects of driver distraction. However, a driving simulator can be also be succesfully applied in a number of clinical applications, especially fear of driving, evaluation of fitness to drive and rehabilitation in a clinic.

Treatment of fear of driving

For clinical psychologist who treat various anxieties and phobias and use exposure therapy to treat their clients, a simulator can be an instrument in the treatment of fear of driving or driving phobia. Exposure therapy involves the exposure of the patient to the feared object or context without any danger, in order to overcome their anxiety. Giving exposure therapy to people with fear of driving in a real car in traffic is difficult in practice: the real risk of accidents is high and always involves a licenced driver instructor as well as a therapist which makes the therapy sessions expensive and difficult to arrange. Also, the environment is in real car in the real word is impossible to control, which is definitely not what a therapist wants. Exposure therapy in a driving simulator to treat fear of driving gives the therapist a controlled virtual environment in which the client is exposed to the anxiety inducing situations without any danger. Virtual reality is used more often to treat phobias.

Evaluation of fitness to drive

Fitness to drive for older drivers and drivers with neurological disorders, after CVA or sleep disorders is typically done by general practitioners using paper and pencil tests, blood samples and eye measurements. However, a simulator can make the fitness to drive test more ecologically valid: it resembles the driving tasks and testing can be done in a structured environment with the same test for all clients. While a simulator may someties be less suitable for the assessment of driving behaviour in older people, because of the increased risk of simulator or cyber sickness in this population, the incidence of simulator sickness can be reduced substantially, when a number of precautions are being taken in the design of the tests. Simulator tests can be a valuable addition to the set of diagnostic instruments to evaluate fitness to drive.

A special branch of clinical applications is the use in a test battery of neuropsychological tests. In a research simulator setup, clinical tests can be developed, for example to evaluate if patients with sleeping disorders are at risk of falling asleep while driving.

Driver rehabilitation and occupational therapy

A driving simulator program can offer a number of practice to people in occupational therapy for the purpose of driver rehabilitation. Especially, turning at intersections, reacting to unexpected events and negotiating fourway intersections and roundabouts can be trained in this group. The goal of driver rehabilitation is to aid individuals with disabilities or age-related impairments maintain independent driving and transportation. This maybe done through the use of specialized mobility equipment and training.


Treatment of phobias with Virtual Reality techniques

A relatively new method to treat phobias is by means of virtual reality techniques. A number of research studies have demonstrated the positive effects of VR in the treatment of several types of phobia, such as fear of heights, fear of spiders, fear of flying and claustrophobia, as well as agoraphobia. New clinics have been established, specialized in virtual reality techniques to treat various phobias.

A car driving simulator is similar to a Virtual reality system, except for the helmet mounted displays (HMD’s). In both types of system, a computer generate world is presented to the client and the client can interact with this world. In the case of a driving simulator, you drive through the computer generated world as if you are seated in a real car and you interact with other traffic participants and the road infrastructure in a very realistic but also safe way.

For driving, the HMD as used in VR is not very well suited, because of the risk of cybersickness that comes with the use of HMD’s. This is aggravated because of two independent types of motions in driving a car:

  • the vehicle moves through the world, controlled by the steering wheel and pedals of the driver.
  • the client looks around in the environment by turning the head (head tracking)

These two types of motions in combination give a high risk of cybersickness in a VR system. The brain is not very well able to distinguish these movements. This is the most important reason that a driving simulator is a much better solution for the treatment of driving phobia or fear of driving: in a driving simulator the risk of ‘simulator sickness’ is a lot smaller, especially if the simulations are designed to keep lateral and longitudinal accelerations to a minimum.


Drinking while driving

Drinking while driving (DUI) is still one of the main factors in accident causation. Alcohol is involved in  over 25% of all car crashes in the US and a number of European countries. This makes alcohol the most important factor in accident causation in traffic. Especially young male drivers are affected. Young male drivers generally are inexperienced drivers and they tend to overestimate their driving skills and underestimate the effects of alcohol on their driving performance. Also, people under 20 often don’t ‘feel’ the effects of alcohol which causes them to drink much more than others. To read more about the accident risk of young drivers, click here… To read more about the effects of alcohol on driving performance, click here….

A car simulator that simulates the effects of alcohol will make them more aware of the negative effects of alcohol on driving performance. The effects of driver impairment, or driving under the influence (DUI) are simulated by:

  • blurred vision
  • slowed reactions and impaired motor performance resulting in swerving and reaction delays in braking

Alcohol also increases overconfidence which, ofcourse, can not be simulated easily. The impaired driving simulation practice shows the effects of driver impairment by comparing driver performance in two conditions:

  • normal driving
  • impaired driving

by showing the results on number of collisions and driving off the road, and crossing the center line. During the drive, a number of different hazards have to be coped with, such as a dog that crosses the street, a passenger that crosses the street from behind a stopped bus, people on a zebra crossing near a school, cars driving off from the side of the road, oncoming traffic, a lead vehicle that brakes unexpectedly etc. This practice will make young drivers aware of the dangers of impaired driving (DUI) in a way that can’t be demonstrated in a real car on public roads.