Driver fatigue is used as a catch-all for driving when you are too mentally or physically tired, or sleep-deprived. Whatever the cause, driving when you are tired is extremely dangerous.
If you have to drive, getting sufficient sleep beforehand is essential – at least seven hours in every 24. The most important message about tiredness is don’t let it happen. Get enough sleep before your shift so you can stay awake and alert through all of it and during the drive home.
Prevention is the best option by a country mile – because there really isn’t a cure. When you are tired – i.e. need to sleep – your brain starts to shut down several key functions, including visual and sensory processing, emotional regulation, decision-making, depth perception, spatial attention… you get the picture. All the cognitive functions you need to drive start to disappear. The brain does not ask permission, and it can’t be stopped – but it will give you warning signals.
Drivers who notice sleepiness – excessive yawning, heavy eyelids, etc – often have collisions within 15 minutes if they continue to drive. (C.Anderson et al, 2023 Feeling Sleepy? Stop Driving: Awareness of Fall Asleep Crashes)
If you feel sleepy, pull over as soon as it is safe and legal to do so. If another driver can relieve you, phone it in and sleep until they arrive. Caffeine may help for a short while, if coupled with a nap – but it won’t last long, so make smart decisions.
If you feel sleepy, you are very likely to have microsleeps. You might not even be aware of this, as they sometimes only last a couple of seconds. However, that might be the last couple of seconds of your or someone else’s life.
Drowsy driving is as dangerous as driving when drunk – possibly more so.
Excessive day time sleepiness
There are various medical conditions which can cause excessive day time sleepiness (EDS), including obstructive sleep apnoea, insomnia and narcolepsy. People with these conditions often feel sleepy when a passenger in a vehicle, watching a movie or when they are bored.
If you think you are tired without an obvious cause, or fight off sleep during the day, then see your GP. Most conditions which cause EDS can be treated, and once you are treated you can continue to drive safely.
If you ever feel too tired to drive, or know you haven’t had enough sleep for the drive ahead, tell your employer. It’s far better to speak up than to risk a collision.
Caffeine
Caffeine brings problems of its own. It binds to adenosine receptors which cause sleepiness. It takes around 10 minutes to take effect and peaks in the bloodstream after 45 minutes to one hour. This can make you feel a little more awake, but if you need sleep, caffeine won’t necessarily make you safe to drive.
Caffeine stays in your system for several hours, so it can disrupt your quality of sleep when you finally get to bed.
Relying on caffeine can therefore become a vicious cycle of stimulants and poor sleep leading to more stimulants and poorer sleep.
Health issues
Sleep isn’t just important for driving. Did you know that not getting enough sleep also significantly increases your risk of cardiovascular disease, stroke, diabetes and dementia? This is because sleep has a vital physical function. It’s when we repair tissues, clean the brain of toxins and lay down long-term memories (among other things). It’s way too important to miss out on.
Too little sleep over extended periods compromises our ability to learn, to heal and to make decisions. It adversely affects our mental health and mood, and degrades concentration, motor skills and stamina.
Task fatigue
It’s also worth noting that sometimes we get ‘tired’ of a specific task, particularly if it is repetitive. This isn’t to do with sleep but rather specific areas of the brain becoming congested. It can mean you stop being observant, lose focus or attention, or become clumsy – in other words, your performance degrades.
Take a break, have a drink, have a conversation, move around. These things give the brain a chance to recover.
Tips to stay alert
- Avoid heavy meals before driving.
- The key times for sleepiness are midnight until 6am and 2-4pm, so either schedule around these, or make sure you are well rested and awake.
- Take regular breaks, move about and talk to people – this increases hypocretin, which tells the brain to be awake.
Tips to protect your sleep
- Avoid using screens, having heavy meals or exercising before bed. Turn your phone off.
- Make your bedroom dark and the perfect temperature. Use ear plugs if necessary.
- As far as possible stick to the same times for going to sleep and waking, ideally in line with our circadian rhythms.
Driver Resources – Fatigue
Download a zip file with additional resources to share with your drivers including:
- Short safety messages to send to your drivers on their devices
- Posters for your staff noticeboards and screens
- Information sheets from DfBB’s Driver Toolkits