Driving experiment: Biggest distractions behind the wheel

Distracted driving is a real problem on our roads. In 2022 alone, there were a reported ​136,000 road accident casualties in the UK, and our recent report found that nearly ​one in five (17%) incidents are caused by impairment or distraction of the driver.

Whether you’re eating a sandwich, or asking Siri to phone a friend, any kind of distraction behind the wheel, legal or not, can have a big impact on your focus. But which situations can increase driver reaction times the most?

To find out, we conducted an experiment of 10 drivers, who carried out reaction time tests for various scenarios while behind the wheel of a parked car*. The research found that ​​every distraction had a negative impact on driver responses, causing reaction times to slow by a minimum of​ 54%.

What are the biggest distractions when driving?

When the drivers carried out the reaction tests with zero distractions, the average response time was​ 334 milliseconds. This was then compared with the reaction times recorded while the tester subject engaged in various activities, to determine which scenarios impacted driver concentration the most.

​​It’s important to note, that even if a distraction isn’t technically deemed to be illegal in its own right, if the activity is significant enough to affecting your ability to control your vehicle safely, then it can become illegal. The penalty for dangerous driving is an unlimited fine, 3 to 11 points on your licence, and even potentially two years in prison.

1. Reaching to get something from the back seat

The experiment found that ​reaching to get something from the back seat was a major distraction for drivers. In this scenario, the reaction times of the drivers increased by a huge ​172%, with an average time of ​909 milliseconds.

Whether you still have your eyes on the road or not, this kind of physical distraction means both hands aren’t on the wheel, significantly reducing your control of the vehicle. ​Keep both hands on the wheel at all times, and ​if you do need to grab something, whether it’s from the back seat, or even next to you on the passenger seat or footwell, it’s advised to pull over so you can do so safely.

2. Changing the radio on the console

Increasing driver reaction times by ​144%, ​changing the radio or music on a vehicle’s console is another highly distracting thing to do behind the wheel.

​​Even if the radio has gone static, or your least favourite song in the entire world has just shuffled on, be cautious and only adjust the controls at a calm moment when it’s safe to do so. If your car has controls on the steering wheel, try to use these instead, so you can keep both hands on the wheel. ​To be extra safe, pop your playlist on or choose your radio channel before you set off, and if you need to make any significant changes, pull over to do so.

3. Texting

​​​Texting while driving is​ illegal, and ​​doing so could increase the risk of crashing by 23 times. Our experiment found that driver reaction times increased by ​​132% when messaging on a hand-held device.

​​Dialling and ​talking on a hand-held mobile phone while driving is also ​illegal. We found that these activities also significantly affected response times, with a ​115% and a​ 93% increase, respectively.

Drivers should never text, dial, or talk on any kind of handheld device while driving. Not only will this stop you being landed with some hefty fines and penalties, but it will also keep you and other drivers safe when on the roads.

What are some of the less obvious in-car distractions?

All of the above situations take your eyes off the road, which means it’s perhaps not surprising that they ranked as the biggest distractions. However, the experiment has also shone a light on some other behind-the-wheel scenarios, that we might not realise can impact our focus when driving.

1. Drinking from a water bottle or coffee cup

Whether we’re hydrating after the gym or grabbing a caffeine boost on a road trip, lots of us may have ​si​pped from a water bottle or cup when in the car. We found that this is the considered to be another big distraction, causing an increase of ​125% in driver reaction times.

Drinking from a bottle or coffee cup can impact your control of a vehicle, especially when it requires you to tilt your head back and take your eyes off the road. The better option would be to invest in a bottle, or cup, with a straw, so you can maintain your concentration on the traffic ahead.

2. Eating

Although not illegal, ​eating behind the wheel can often be quite dangerous as it requires you to remove at least one hand from the wheel. Our experiment found that eating increases reaction times by ​​118%, making it another major distraction for drivers.

​​Try to eat before you set off, or if you must eat mid-journey, do so when the car is parked. While it might feel like a timesaver to munch on the go, it’s not worth having your hands off the wheel. There’s plenty of service stations across the country, so look out for the nearest one on your journey and have a quick bite to eat there.

​3. Using Siri

​​​While​ speaking with Siri (or other voice-controlled devices) ​isn’t illegal, it can still be distracting when you’re driving. Our experiment found that when it comes to using voice assistants, ​asking Siri to play music was the one of the most distracting scenarios, increasing driver reactions by ​116%. When ​Siri was used to call someone, driver reactions were impacted by ​68%, and even ​listening back to a text message read out by Siri saw an increase of​​ 55%.

​​Hands-free use of your phone while driving is legal, but it must be set up correctly with a handsfree aid, such as: a built-in voice command computer, a dashboard phone holder, or a windscreen mount. Make sure any hands-free phone is securely attached to the windscreen or dashboard and doesn’t obscure your view of the road.

Given that using voice assistants can still impact your focus while on the roads, we would recommend keeping interactions with Siri to a minimum when driving or wait until the car is safely parked to make any commands.

​4. Dancing

Causing a ​​97% increase in reaction times, ​​dancing to music while driving is another big distraction. Dancing or singing while driving in itself i​sn’t illegal, but again, ​​if you’re seen to be particularly distracted from the road, then this can cause significant ramifications.

Whether you’re belting out your favourite ballad, or shimmying to the latest number one, keep both noise and movement to a minimum to ​​ensure you have full control of the vehicle at all times.

​5. Changing the temperature in the vehicle

As we head into winter, a lot of us will feel the need to crank up the heating when we’re on the go. However, we found that r​eaching to change the temperature in the vehicle could increase a motorists reaction time by ​​62%.

Just like with your music, make sure to adjust your temperature before you set off, and if things get a little too warm, remain cautious and only reach for the controls if it is a safe moment to do so. If you think it will be a big distraction, ​​pull over so you can make any changes safely.

Sources & Methodology

* Disclaimer: the reaction time tests were all conducted while the engine was off, and the vehicle was safely parked.

Compare the Market conducted this experiment on 10 British drivers, who’ve held their licence from 2 - 17 years. The reaction test was carried out behind the wheel of a parked car with the engine off, with a laptop placed on the dashboard of the car, while they completed 15 different distractions.

The first test was done with no distractions to get a base reaction time. Drivers then carried out the reaction test whilst acting out each of the 15 distractions. An average of all the reaction times was calculated for each distraction and this was compared with the ‘no distraction’ time to determine the impact on driver reaction times.

To determine the rules around distracted and dangerous driving the following sources were used:

• Police.uk
• Gov.uk Highway Code