Uswitch

Reaction times

What factors have the biggest impact on your stopping distance?

How well you can spot and react to potential hazards on the road can mean the difference between a safe journey and an accident. As well as varying from one person to the next, reaction times can be impacted by a whole host of external factors, from the driving conditions to who else is in the car with you.

But how big of an impact can these factors actually have?

Key Findings

Of all the factors we studied, the following stimuli will help reduce your stopping distance the most.

Reductions in stopping distance when travelling at 70 mph:

  • 23.92m Drinking a coffee
  • 21.48m Being female
  • 15.49m Listening to rap
  • 13.49m Noisy kids in the car

Key

  • m | meters
  • mph | miles per hour

Minus stopping distance | faster reaction time | car stops sooner than average

Positive stopping distance | slower reaction time | car stops later than average

To find out more, we partnered with behavioural science consultancy, CX Lab, to create our own unique reaction times experiment, recruiting 103 drivers to take part.

Our participants all watched a number of clips taken from the official DVSA Hazard Perception Test, where they had to click a button upon spotting a hazard. After establishing their baseline reaction time, we had the participants complete the test again, but this time introduced one of the following factors:

We were then able to see the impact each factor had on our participants’ reaction times, as well as calculating what this equates to in terms of the difference in stopping distance from our control group.

  • Music Participants listened to rap, techno, heavy metal, classical, jazz or R&B
  • Caffeine Participants were asked to drink a strong cup of coffee 20 minutes before the test
  • Noisy children Participants listened to an audio track of noisy children

We were then able to see the impact each factor had on our participants’ reaction times, as well as calculating what this equates to in terms of the difference in stopping distance from our control group.

Interact with the data visualisation on the right to see what we found.

Interact with the data visualisation below to see what we found.

-25m
-20m
-15m
-10m
-5m
0m
5m
Coffee -23.92m
Rap-15.49m
Noisy kids-13.49m
Techno-5.55m
Heavy Metal-3.16m
Classical-2.79m
Jazz-1.29m
Control
R&B+4.24m
-25m
-20m
-15m
-10m
-5m
0m
5m
Coffee -23.92m
Rap-15.49m
Noisy kids-13.49m
Techno-5.55m
Heavy Metal-3.16m
Classical-2.79m
Jazz-1.29m
Control
R&B+4.24m

How did men and women compare?

On average, our experiment found women to be faster at spotting hazards, responding 690ms faster than men. In a car travelling at 30 mph, this means women would stop 9.21m sooner than men would. However, when travelling at 70 mph, this stopping distance increases even further, with women stopping 21.48m earlier than men.

Female difference in stopping distance (m)
-25m
-20m
-15m
-10m
-5m
Male
stopping point
70mph
40mph
30mph
Faster stopping distance

Which genre of music has the biggest impact on reaction times?

Out of the six different genres of music our participants listened to, rap had the most positive impact on reaction times and stopping distance. In a car travelling at 70 mph, participants listening to rap music would stop 15.49m sooner than those listening to no music at all.

At the other end of the scale, people listening to R&B had the worst reaction times, stopping 4.24m later at 70 mph, when compared to people listening to no music.

  • 30mph
  • 40mph
  • 70mph
-20m
-15m
-10m
-5m
Average
stopping point
5m
10m
Rap
Techno
Heavy Metal
Classical
Jazz
R&B
Faster stopping distance
Slower stopping distance

Does caffeine improve your reaction time?

Out of all the factors we tested, caffeine had the biggest impact on results. When participants had drunk a strong cup of coffee 20 minutes before taking the test, they responded quicker upon spotting a hazard, which would lead them to stopping 23.92m earlier when travelling at 70 mph, compared to people who had no caffeine in their system.

With coffee difference in stopping distance (m)
-30m
-25m
-20m
-15m
-10m
-5m
Without coffee
stopping point
70mph
40mph
30mph
Faster stopping distance

What impact can noisy kids have on your reaction time?

When listening to the sound of noisy children, participants actually reacted faster upon seeing a hazard, equating to an improvement in stopping distance of 13.49m when travelling at 70 mph.

With kids difference in stopping distance (m)
-25m
-20m
-15m
-10m
-5m
Without kids
stopping point
70mph
40mph
30mph
Faster stopping distance

Concerned about road safety? Take a look at the UK’s safest and most dangerous roads, according government data, and make sure your car insurance and breakdown cover are up to date.

Data and methodology

We partnered with behavioural science consultancy, CX Lab, to create our own unique reaction times experiment, using 16 different clips taken from the official DVSA Hazard Perception Test (HPT). Participants were instructed to watch the clips and press space when they spotted a hazard.

Participants first carried out the HPT with no sound, to establish a baseline for each as a control condition. These same 16 clips were then edited to include audio, with 6 different music tracks (rap, techno, heavy metal, classical, jazz and R&B), as well as a track featuring noisy children. Participants completed the HPT again, with one of the soundtracks, allowing us to compare this to their control baseline. Finally, participants were asked to complete the HPT 20 minutes after drinking a strong cup of coffee, again comparing this result to their control time. The experiment was designed in such a way so that no participant would view any individual clip more than once.

Our experiment took place between December 2020 and January 2021 and consisted of 103 participants, equally split between men and women, aged 18 and upwards. There was a mix of driving experience, with 35% of the sample having held a UK driving licence for over 25 years, and the majority driving at least 4 times per week.