Introduction to the Sense of Hearing and Road Safety
Driver fitness is one of the important requirements for safety on the road. We have, on the Arrive Alive website discussed many of the factors that contribute to reduced driver fitness - including intoxication, fatigue, poor vision etc. We have also discussed specific groups of road users that might have a reduced fitness to drive – such as young drivers, elderly drivers, drivers with Alzheimer’s etc.
We would however also like to pay closer attention to the sense of hearing - and how important this sense might be for our road users! It is generally accepted that the more senses to be used when travelling – the better for safety on the road. Of all the senses of sight, hearing, smell, touch and taste - it is perhaps only taste that is not closely associated with safety on the road!
The senses most involved are eyesight and hearing, which provide us with information necessary to act adequately in a traffic situation. They are not merely there benefitting road safety – they develop hand-in-hand with experience. Coping with road traffic not only requires a certain level of eyesight and hearing, but also road traffic experience.
For cyclists it is also a sense of balance, the sense of touch and the sense of body positioning which makes it possible to ride a bicycle even with eyes closed. Two of these three senses aren't even in the usual, incomplete list of five senses. After balance and touch comes sight, which makes it practical to ride where there are things you might run into. And then there is hearing...
In this section we will consider the relation between the sense of hearing and road safety. It has been alleged that hearing-impaired and deaf people who use their eyes can often make safer drivers – and this is something we need to investigate and discuss.
Hearing for a variety of road users
Hearing is not something only to consider with a view to the deaf driver – but also when considering children, the elderly and those road users who are only slightly impaired. We also need to consider the hearing not only for the driver, but also the biker, the cyclist and even the pedestrian!
Specific groups of road users might well experience specific limitations in traffic. Children have limitations in traffic and these include that
- Their hearing and their eyesight are not fully developed
- Their field of vision is narrower, that is they have a bad wide-angle vision (peripheral vision.)
- They are bad at judging the source of a sound etc
The development of perception is not instantaneous, but indeed a floating transition from the immature nervous system to the well developed senses of an adult. We will consider how the sense of hearing could reduce safety and discuss measures to improve safety on the road for those who are hearing impaired.
Hearing and the Need to Avoid Driving Distractions
It is not possible to discuss the importance of hearing without also briefly referring to the dangers of distracted driving to road safety. A road user – whether it is a driver, pedestrian or cyclist needs to be alert and vigilant at all times. To be vigilant the road user needs to pay close attention to traffic and road hazards around him – and for this he/she needs to use the senses available.
It is not only the hearing impaired who might experience the reduced benefit of senses in the traffic environment. Some road users are perfectly capable of using their senses of hearing, sight etc – but simply reduce the effect thereof through distracted driving and behaviour on the road!
Many road users take their hands of the wheel to use a phone, tune in the radio or CD, eat a sandwich or have a drink and they play their radio or CD too loud and cannot hear outside noise. Not only is listening to telephone calls and communicating or quarrelling with another a driver distraction – but especially so the tendency to send text messages while driving!
Research in the US has revealed that thirty-four percent of teens aged 16 and 17 who text said they have texted while driving, while 52% of cell-owning teens said they have talked on a cellphone while behind the wheel.
A survey conducted by the Association of British Insurers (ABI) found that 72% of motorists considered drivers using mobile phones as the biggest danger on the country’s roads. There has also been much debate on the use of headphones and music devices such as the iPods by cyclists when cycling on our roads.
Motorists’ organisation the AA has added its voice to the debate, with its president Edmund King - himself a keen cyclist - calling on the Department for Transport (DfT) to warn cyclists about the dangers of listening to MP3 players while cycling. He was quoted in The Sunday Times as saying: “They’re meant to be mobile, but if you are cycling, you need all your senses about you.”
Many pedestrian accidents have recently been contributed to pedestrian inattentiveness brought about by the trend of listening to music from iPods when crossing the road. Road safety campaigners have also warned young pedestrians of the dangers of crossing the road while listening to music, whilst admitting that it is not a matter of banning or legislating these devices – but rather of a need to raise awareness.
There is a need to raise awareness of the dangers to road safety when we take one of the key senses away!
Why is hearing important for safety on the road
We are all well aware of the importance of clear vision to road safety – but might not be aware of how our hearing assists us to greater safety on the road. We would like to pause for a moment and reflect on how our hearing helps us to avoid accidents:
- Under noisy urban conditions, the sense of hearing provides an early warning
- Our hearing provides information about nearby vehicles, their sudden braking or hooting.
- On a crowded street, only especially loud sounds such as car horns can provide an early warning.
- Hearing ability enables us to know where sound is coming from.
- It tells us about honking horns, approaching ambulances and fire truck sirens etc
- In quiet (typically, rural) surroundings, the sense of hearing can sometimes alert a bicyclist to a motor vehicle, a charging dog or another potential hazard before the bicyclist can see it.
- Hearing helps detect unseen hazards behind a cyclist or jogger – hidden or obscured by vegetation or another obstacle.
- A bicyclist might hear a car a mile away under quiet conditions, upwind and on level terrain.
- Hearing allows us to detect weird engine noises
The Deaf and Ability to Drive Safely
What are the specific road safety risks to the hearing impaired?
Bleckly (2008) lists some possible issues for deaf or hearing-impaired drivers:
- using hands to sign, especially if using two-handed sign language to communicate within the vehicle
- lip reading a passenger while driving
- hearing emergency sirens, car alarms and other important sounds
- knowing where a sound is coming from
- communicating with the police or with road assistance personnel
- hearing your car alarm
- hearing seatbelt or other warnings your car may give
The dangers of distracted driving apply to both the hearing and the deaf road user. Lip-reading or signing while driving can become an issue if they are not managed well by the hearing-impaired or deaf driver - in the same manner that very loud music might distract the driver with perfect hearing.
What does research tell us about deaf drivers and road accidents?
Research shows that deaf drivers do not have more accidents or fines than hearing drivers, so there should be no reason why the deaf cannot drive.
It is interesting to note that the right-of-way rules in the traffic law are based on the sense of sight rather than hearing. A vehicle operator's only hearing-related duty under the traffic law is to respond to special warning devices: horn, siren or bell. Despite this duty, no laws prohibit deaf persons from operating either a motor vehicle or a bicycle. Not only this, the only laws restricting sound systems on or in a vehicle are intended to reduce disturbance to people outside the vehicle.
We would like to pause at some of the research done on medical conditions and safe driving:
Dobbs (2005) reviewed research from 1960 to 2000 on medical conditions and driving. She found that few studies have ‘examined the relationship between hearing impairment and risk of motor vehicle crash’. Two reasons for this come to my mind. Firstly, statistical analysis would need to analyse many factors involved in the ability to drive, such as managing environmental factors (heavy rain, for example). Secondly, as there are so many factors to consider, identifying explanatory variables(such as hearing loss) with a statistically high correlation to road crashes can be difficult to obtain.
Several studies had mixed and often inconclusive correlations between hearing impairment and risk of vehicular crashes. Based on so few studies, Dobbs concluded that there is little evidence of hearing loss being a potentially higher risk factor contributing to car crashes.
Fitness to drive guidelines
Which info is available on hearing impairment and fitness to drive guidelines internationally?
Despite the limited research, guidelines and standards do exist for health professionals to assess patients for their ‘fitness to drive’. Australia’s guidelines are produced by Austroads, an organisation whose members are the Australian and New Zealand road authorities. Every few years, Austroads reviews the ‘fitness to drive’ guidelines by consulting representatives from academia, governments, industry and the community about various medical conditions (including hearing loss) and their implications for driving. This review process would take into account up-to-date anecdotal and statistical evidence and professional opinions.
Australian road safety policymakers do not consider hearing loss to be an impediment to safe driving in the 2006 Austroads guidelines. In fact, the guidelines state that ‘mild to moderate hearing loss does not appear to affect a person’s ability to drive safely. It may be that a loss of hearing is well compensated for since most people who are hard of hearing are aware of their disability and therefore tend to be more cautious and to rely more on visual cues.’
Guidelines on medical conditions and specific symptoms
There are however specific guidelines recommended for road users with other medical conditions. It is prescribed that people who have ‘vestibular disorders’ or difficulties with conditions such as ‘acute labyrinthitis, vertigo, Meniere’s disease, recurrent vertigo or horizontal head movement’ should not drive while these symptoms are present, whether temporary or not. Unfortunately, these conditions are often associated with hearing loss. If present, affected people are advised not to drive, as the driver may unexpectedly lose ability to take evasive action or use defensive driving tactics.
The guidelines place no restrictions on a hearing-impaired or deaf person driving a private car (unless they also have a vestibular disorder). Austroads comments that ‘while hearing loss is not considered to preclude driving a private car, persons with severe hearing losses should be advised regarding their loss and their limited ability to hear warning signals, etc. Engineering solutions such as additional mirrors (as mentioned above) might also be recommended upon consideration of the needs of the individual driver.
Hearing Aids / Hearing Devices and Road Safety
Many companies are continuously inventing newer, improved hearing aids everyday! We would like to briefly focus on hearing aids and whether this technology can assist the hearing impaired to be safer on the road.
We can identify 2 main groups of hearings aids:
- Conventional Hearing Aids: They include digital and analog, behind-the-ear (BTE), in-the-ear (ITE), in-the-canal (ITC), etc. – pretty much all the hearing aids most people have ever heard of.
- Implantable Hearing Aids: These are different from conventional aids in that either a portion of the aid or the entire aid is implanted within the body. They are fairly recent additions to the hearing aid world and provide superior hearing support for people with certain hearing loss characteristics.
How do Hearing Aids Work?
Hearing aids work by amplifying the functioning part of your hearing, but they can do nothing to restore the hearing that has been lost. It’s important to understand this -successful hearing aid use does not mean hearing everything you hope to hear. It means hearing much better than you otherwise would hear.
Do we need hearing aids on the road?
Hearing aids might be very important for those who still have some hearing and who sense that they are losing their hearing bit by bit. Hearing aids can assist in improving the hearing and speech understanding of people who have suffered hearing loss that comes from damage to the small sensory cells in the inner ear, called hair cells. This type of hearing loss is called sensor neural hearing loss.
The damage can happen as a result of illness, aging, or injury from noise or certain medicines. A hearing aid magnifies sound vibrations entering the ear. Surviving hair cells detect the larger vibrations and convert them into neural signals that are passed along to the brain.
The greater the damage to a person’s hair cells, the more severe the hearing loss, and the greater the hearing aid amplification needed to the make up the difference.
Persons with hearing aids should be encouraged to wear them when driving.
Advice to those struggling with hearing
If you sense that you are suffering hearing loss and might benefit from a hearing device, best is to visit your physician, who may refer you to an otolaryngologist or audiology. An otolaryngologist is a physician who specializes in ear, nose and throat disorders and will investigate the cause of the hearing loss. An audiologist is a hearing health professional who identifies and measures hearing loss and will perform a hearing test to assess the type and degree of loss.
If there is still some hearing in the worse-hearing ear, a hearing aid may be helpful. This will depend on the degree of hearing loss and on how well the hearing impaired ear can use sound amplified by a hearing aid. The use of a hearing aid might not only provide more hearing –but also increase the confidence of the road user – driver, cyclist or pedestrian next to the road!
It is best not to wait – hearing will not suddenly return, but rather diminish over time. The hearing aid that will work best for you will depend on the kind and severity of your hearing loss.
There is no reason why the hearing impaired should be regarded as more of a risk than any other road user. It is also true that the deaf and hearing impaired are well aware of the risks and have sharpened their other senses to assist them to be even more vigilant and alert on the road.
It is the responsibility of all road users to pay close attention to their own driving abilities and weaknesses and to do everything possible to protect the lives of all road users!