The Physics of Road Safety

The Physics of Road Safety.

With the changes to the Scottish School Curriculum it was decided to make mechanics courses applicable to all students. Living in a rural area many students learn to drive on farms and believe they have little to learn when they begin driving on roads. There have been many fatalities in our Region; even one of these fatalities is prevented then the work would have been worthwhile. We cover work for all ages from 11-18 year of age.

With some basic equipment students can be taught Physics through Road Safety at all levels.


Figure 1: An example of a playmat for students to measure distance and time and calculate average speed. Also used for instantaneous speed and velocity.


Figure 2: students finding average and instantaneous speeds with playmats.

I use playmats and toy cars for the 11year olds. Students use string and a stopwatch and calculate the average speed to drive a predetermined route around the playmat. Already potential driver attitudes are visible. Some students race around the track as fast as possible just trying to get the fastest average speed, other meticulously obey road rules, even making up indicator sounds at the junctions. We then discuss speed and its role in many road traffic incidents. This leads nicely into instantaneous speed and the difference between the two. Using light gates and interfaces we calculate the instantaneous speed as students drive vehicles along a straight stretch of the road. We discuss the similarities between this and the traffic cameras. If playmats are too expensive a route can always be marked out on paper or chalk across the floor or table.

We then use Fifex reaction timers to introduce the idea of reaction time and how this affects the measurement of instantaneous speed. There are many online games, many related to driving that can also be used to check the students’ reaction times.

We then play a game with the reaction timers called Chicken Run. Using the pre-programmed reaction timers students estimate a virtual drivers’ stopping distance under various conditions and the effects of not concentrating on the likelihood of an accident. Two “drivers” use a steering wheel from a games consul to “drive” the vehicle. The road conditions and the speed of the car are set on the reaction timers. The rest of the students estimate the stopping distance; trying to choose a value as close to the stopping distance as possible without being “hit”. The drivers start by hitting the green start button and when the red light stops flashing the student has to hit the stop button and the reaction time, thinking and braking distance are displayed on the screen. The students calculate the stopping distances by adding the thinking and braking distance.  We start off at a low speed on a dry road and gradually increase the speed, road conditions and distractions. For example a student might select to drive at 30 mph in the dry without distractions. Initially the students have little idea of the stopping distance, and in the first few rounds most are hit by the driver.  This game has some serious messages, despite being fun. By dividing the class into two groups and having two drivers it adds to the fun, and can demonstrate to students how some drivers might “hit” you but others not. We look at the effects of texting, music distractions and road conditions. It is important to mark out these stopping distances  as students have no concept of distances. If the reaction timers are too expensive then a small computer programme could manage the same calculations and the students can run the same tests. The company make a version with foot pedals so that it is more realistic to find the impact of drinking from a bottle and texting whilst driving.

reaction timer

Figure 3: Fifex Reaction Timer for measuring reaction times and recording thinking, braking and stopping distances.


Figure 4: Driver playing Chicken Run


Figure 5: Two drivers playing chicken run

Obviously this device is programmed for the UK market and has the speed in miles per hour, but a version is available in km/h. Students are shocked at how long it takes a car to stop when being driven at the speed limit in icy conditions.

It is not too big a leap to introduce velocity and the difference between speed and velocity. As the playmats are 2D it is easy to get students to realise the difference between how far they’ve travelled (distance) and how far they are from the start as the crow flies (displacement). This helps explain why v is the symbol for speed. Many students now have a compass on their phones and the angle or bearing can be taken to indicate the direction of the vector.  There are various routes through the course after speed is completed. Students can be taught about forces and the effect of collision. The EU car safety scheme can be discussed culminating in students trying to build a safety device for the car to reduce the forces received during a crash. Generally, despite all the knowledge, students tend to produce something that bounces rather than crumples resulting in many smaller but potentially damaging forces on the passengers. We call this exercise “Tart Ma Kart”, based on the TV show “Pimp My Ride”.  Acceleration can also be fitted into the Road Safety theme and can include choosing a car with a five star safety rating and choosing a car with a high acceleration.

At the end of these activities the students work in the hall where a 1/3 scaled model of a road traffic incident is laid out. We were sponsored to be able to source the materials for this, but with a little imagination, or support from students this could be done with cardboard boxes or borrow from the students if they might have had a ride on car.

Students secure the scene and formulate a hypothesis for what occurred. They are given two witness statements and have to note the similarities and disagreements. Witness statements are not used in any meaningful way in a road incident as they are so unreliable. A book of information is given to the students with details of the road surface and the differences between run under and run over and a talk about the four stages of braking. The scenario is based on a real local road incident and this makes it poignant for the students.

Students measure out the tyre makes and use the equations  to discover the speed the pedestrian was hit, the initial speed of the car when the tyre marks were laid down on the road and what would have happened if the car had been driving at or below the speed limit.

IMG_9337 (Small)

Figure 6: Layout of part of the scene

police simulation

Figure 7: Police reconstruction of the scene.

There is a great sense of achievement when the students finally work out what happened and get the correct answer. Many need a little prompting but the satisfaction is immense. We were lucky enough to have the police in when we were completing this task but it isn’t necessary. It just adds to the knowledge and experience that can be given to the students and allows careers advice to be given.


The senior students receive a talk by a Road Crash Investigator around a serious incident occurring in 2006. The police discuss the evidence and explain how the timeline of what occurred can be built up from the evidence of the scene. The students are then given the age and profile of those who caused the accident. The Road Investigator then provides details of the people causing the fatalities and it is a shock to them all. The final task is for the students to use their knowledge of impulse, conservation of momentum and equations of motion to look at two A1 plots of road incidents and being asked to use the evidence to find out what happened.

the Glen 1

Figure 8: The Glen, one of the worst road crashes in Dumfries and Galloway, and caused by young drivers


2 vehicle

Figure 9: Senior Students use an A1 plot to determine the cause of a road traffic incident.

All students involved in the work benefitted to some extent and it engaged students who might otherwise think Physics is not for them. Much of the work can be adapted for local situations and local police road crash investigators might be able to provide more examples of local incidents that can be used. The two examples that we have been given can easily be adjusted to show drivers on the other side of the road or travelling at local speed limits.


bbc news

Figure 10: The Glen – one of the worst ever road traffic collisions in our Region and caused by young drivers.

Figure 11: Our work was showcased at the 2014 Royal Society Summer Science Exhibition


Road Crash Materials

Lower school

Middle School

Selective Attention Test (original) (advanced)

Reaction Times!.aspx

The Glen Road Crash

Fifex Reaction Timers



Where It All Began!

It is hard to say where the Road Safety Initiative began and each time I think of a starting point I am reminded of something else we did previously. I currently believe the starting point was with Brian Redman and Gregor Steele and their “Tart Ma Kart”, aka “Pimp my ride copyright!”

Gregor Steele- The Man behind Tart Ma Kart
Brian Redman- who took Tart Ma Kart on the Road thanks to the IoP

In the Tart Ma Kart project (supported from a grant from the Institute of Physics) students had to produce and design a crumple zone for the front of the car using special high-tech materials. Most students chose materials that would actually make the crash worse, as they caused bouncing. Only one group made a successful crumple zone.

The students then discussed their thoughts on this experience and created an informational display and presentation to share with the community. They researched safe cars and learned about the different important safety features. In the presentation, they included their findings from the many discussions they have had on the topic of safe cars. All of this aimed to share a very important message – that the type of car you drive could affect whether you survive an accident, so choose carefully!

I think after this Mrs Physics did the Summer School at SSERC (highly recommended) and we were given a Fifex Reaction Timer.

Fifex Reaction Timer, fun for old and new. I can see this becoming a party game.

Then came the Magnox grant and the idea of making all of our dynamics and mechanics relate to Road Safety (see separate post), and finally came the work with the Road Policing Department, under Inspector Neil Hewitson.

Finally over lots of cups of tea and coffee and too many cakes, we came up with Be A Road Crash Investigator, and the A1 boards for the Higher Physics groups.

I am sure we’re not finished there. The next group of Road Safety officers in School want to educate family and friends on Safe Driving…. so watch this space!




Be A Road Crash Investigator

Be A Road Crash Investigator is a partnership project with Police Scotland and funded by the Royal Society and the Radcliffe Trust, with support from Scottish Schools Education Research Centre (SSERC).

The project is designed for use across all levels of Physics.

the glen 2

Following on from a high profile fatal crash in the region in which three young people were killed it was felt that more education needed to be carried out to illustrate to young people the dangers of driving fast on the roads network. At the same time the methods used to prove the speed and behaviour of the vehicles prior to the crash were found to be highly pertinent to pupils who were studying maths and physics at school.

the glen

Mrs Physics attended a meeting at SSERC and was supplied with reaction timers that were used in Physics classes to provide examples of stopping distances. This sparked an interest in Road Safety.

Scaling Task
Gregor Steele (SSERC) helping students with our Road Crash Project (Scaling Task)

At the advice of Gregor Steele of SSERC, she contacted Kate Wheaton at Road Safety Scotland, who put her in touch with Inspector Neil Hewitson of what was then Dumfries and Galloway Constabulary.


After a period of communication, Mrs Physics recommended Inspector Hewitson to SSERC for road safety outreach and to give talks on the real life applications of physics and the equations of motion. From this, a successful project was born.

A four tier teaching plan was implemented:

  1. Collision Investigators would attend at various secondary schools throughout the Region and give inputs to S5 and S6 pupils on a high profile crash where three young people from the Region were killed as a result of inappropriate speed. They explain to the pupils how the collision happened and the methods used to calculate speeds using maths and physics.
  2. A successful application for a Partnership Grant from the Royal Society allowed Inspector Hewitson and Mrs Physics to purchase various pieces of investigative equipment including scaled vehicles, measuring tapes, laptops etc. to set up a one-third scale version of an actual collision involving a pedestrian and vehicle.
    Using scale plans, witness statements and some mathematical data pupils were asked to work out from the physical evidence left at the ‘scene’ what speed the vehicle was travelling at prior to the collision and the behaviour of the pedestrian prior to the collision
    Booklets were supplied to each pupil for them to work out what had happened.
     DSCF2107 DSCF21093. lower school kinematics and dynamics would be taught through the work of road safety.
  3. Lower school kinematics and dynamics would be taught through the theme of Road safety
  4. Students would use their knowledge to reach out to adult drivers to produce questionnaire,. the responses will be used to decide an approach to improved driver training.
  5.  Thanks to those who helped Be a Road Crash Investigator
  6. Welcome to “Be a Road Crash Investigator”. We are here today because of some very special people who I need to thank. These are in chronological order.

    1) Gregor Steele, who planted the seed for Road Safety during a week long Physics teacher event.

    2) Inspector Neil Hewitson and his colleagues who have put days of work into this course, who have shared their expertise and have given of their time to make up some excellent resources, such as the scenarios, the computer simulations, the plots and the details of road crashes. Without them we wouldn’t have much knowledge about Road Safety. If you enjoy today please say your thanks by being a careful driver when you get to 17, it is the best pay back they can receive (but you can also say thanks too)

    3) The technicians, Mr Rayen and Mr McEwen, and Dr Hargreaves who spent hours making tyre marks and putting equipment together and didn’t flinch or argue over my weird and wonderful requests.

    4) The janitors and staff (supply staff) who spent hours setting up the cars and floor on Friday until 6pm.

    5) Mrs Macpherson who showed me that I ought to have used publisher in the first place and not word and who made up version one of the booklets.

    6) …and finally to the Royal Society who provided the funds to buy the materials that we can use as part of our course. There can’t be many schools in Britain with 4 ride-on cars, although I have no idea where we will store them!



Our Road Safety Projects Your ideas Your Initiative 2012-14

The ideas S2-S4


To study road safety and make what is learnt in school science relevant by finding ways in which it is used in real life situations. Too many of our students have been killed due to poor driving, and we want to reduce this number. It was decided to partner the traffic police. They were so helpful in sharing their knowledge. The students got to see the crash from the point of view of the police Investigators and it brought home the damage caused by road accidents.

A road crash (1/3 scale) was laid out in the school. Students had to take measurements, complete calculations and read witness statements to determine the circumstances surrounding the crash. This showed students how science is used in crash investigations, how crashes occur and how students can be safer on our roads. Students investigated how to reduce the likelihood of a crash and how they are likely to get caught if they were at fault in an incident. It makes the science they study in the classroom relevant and teaches health and wellbeing.

The Initiatives


  1. We worked with the Dumfries and Galloway Police Traffic Division who put together an amazing set of resources (which we have shared on this website), of some real life road crashes which had been anonomised. Students were then taught about how a crash is investigated by looking at the evidence, taking measurements and following the scientific process. They used the equations of motion to determine the cause. Currently we have two fully simulated crashes but in the next few years it would be amazing if we could increase this, and that as many people as possible use this material in their lessons too. The students found the experience amazing, it made them more aware of road safety and increased their enjoyment of science; to me that is a result. We are learning:
    i.  How a road crash is investigated and the knowledge to look for key pieces of information to assess for accuracy and to see how it can yield information
    ii. To understand and use the scientific process, hypothesising, observing, analysing, evaluating, etc. to determine the cause of a simulated road crash
    iii. To work as a team, to use each person’s skills and draw conclusions from evidence
    iv. To discover situations where kinematics and dynamics are used in real situations, particularly the use of maths at 16+
    v. To use the equations of motion in real life contexts and understand they can be used to draw conclusions from accidents
    vi. To work collaboratively with outside agencies, to understand their job, to see science used in crash investigations and to question scientists about their work
    vii. To be safe road users and to have a better understanding of how to drive safely
    viii. To take witness statements and to find out if these fit with the evidence at the scene of the incident
    ix. To have fun through science and use fun and imagination to solve problems
    x. To test reactions and find thinking distance, braking and stopping distances and see the effect of road conditions and reaction times on stopping distances
    xi. To realise how witnesses are not always reliable when giving a statement due to rationalisation
    xii. The students want to share what they have learned in the community.

Student will go through the stages of a real crash investigation which is laid out as a scene with cars and people at 1/3 scale. A police crash Investigator is on hand to take the students through the investigation stages, to learn how the evidence was pieced together and the causes of the accident, especially how the causes were related to inexperience and youth.

In addition it is hoped the students will get excited by the opportunity to use what they are learning in the classroom and extend this to real-life science Investigations.

Both the teacher and a crash investigator will be present during the work.

We will share this project at the Royal Society Summer Exhibition in London where 10,000 people will hear about road safety.


The ideas S5-S6

The students in class S5 and S6 are older students who are learning to drive, have recently passed their test or will soon be learning to drive – so they are in a prime moment to really feel the impact of road safety education. In their class and with the “Be a Road Safety Investigator” programme, which simulates real traffic accidents and puts students in the role of investigator, they have discussed a wide range of issues.

For example, they discussed the need for cars in their rural area, the figures related to car accidents and young drivers (especially boys), and the risks associated with driving in general. They finally decided that they would like to reflect most of all upon key issues regarding road safety and sustainable mobility in the school’s immediate environment and in the community as a whole.

They concluded that the most important messages they needed to communicate were that young drivers do not take into enough consideration that they themselves can be a risk on the roads, and that they need to be more careful when driving by thinking about speed and risk.

The Initiatives

the Glen 2

The students wanted to get their messages out through a communication campaign aimed at the school and the local community. To do it, they would use information gathered through research and through their experiences with the “Be a Road Safety Investigator” programme.

the Glen 1

For the programme, the police took the students through a local car accident that occurred in 2007. Explanations were given of how the events leading up to the crash were pieced together to bring charges to the three young drivers who were involved – one of these drivers had passed their driving test just the day before. They discussed the causes, which made the students carefully consider their own driving and the responsibility of gaining the keys to a car.

The Glen 4

At the end, the road crash investigators put up the ages of all the people responsible and when they had passed their tests. This was very hard hitting for the students, since they were of approximately the same age. The students will share their findings and experiences with the public – and their material is also being taken up on a national level to become part of the Scottish standard syllabus! A welcome change in education and a triumph for road safety!

Students are then given an opportunity to put their Physics knowledge to the test and are given two further crashes to identify. Working through the equations of motion they are able to find the cause and effects of the road crash. It is a great way to put the students’ course work into practice and at the same time presenting a powerful road safety message.

The ideas S1-S2

When a TV programme about the problems of rural roads was based on the very roads around Lockerbie Academy, the students and teachers knew they had to do something – and they are. Thanks to a grant from The Royal Society, they’ve been able to set up the ‘Be a Road Crash Investigator’ programme in their school.

In preparation for the programme, the students in class S1 discussed various road safety issues like the need for cars in rural areas, the risks associated with driving, the problem of wanting to be environmentally-friendly but living long distances from shops and buildings, the dangers of speeding, and the problem that students have a poor concept of stopping distance and don’t have much knowledge of road safety in general.


They especially focused on the fact that students at their school generally need to be able to drive around the area as soon as they are old enough, because public transport links are poor. Many students live out on farms in rural areas and they can only get a bus to school and later from school – there are no others all day long.

The students also talked a great deal about the different reasons why rural roads have been shown to be some of the most dangerous. In the last few years, they have lost too many students to fatal car accidents – about one person each year.

The Initiatives


The students appreciate that they’ve had the good fortune to be able to take part in the “Be a Road Safety Investigator” programme, so they wanted to organize their own awareness-raising initiative to share what they are learning with others in their community.


The knowledge they are gaining is very unique. The ‘Be a Road Crash Investigator’ programme brings road crash investigators into the classroom, and brings students to the scenes of local accidents – almost. The investigator and his team use high tech equipment to re-create crash sites of real accidents that happened in the area, complete with tire skid marks are video recorded testimonies of the “witnesses”. Then he works with the students to go through the entire process of collecting evidence, analyzing it, and piecing it together to determine how the accident happened, and why. Often times, the cause is related to inexperience and youthfulness, creating a powerful impact on the students.


They will later share their experiences through the awareness raising campaign, which will begin once students have been through several accident simulations and have acquired enough information and experience to offer really valuable insight. Then they will be able to take what they’ve learned to public events to get others involved. Through the campaign, they would most of all like to share the message that everyone needs to be responsible for their actions on the road and drive more carefully.



Magnox Grant

CX/11/47                             10 January 2012

Lockerbie Academy Partnership with Magnox Ltd and D&G Police completes Road Safety Project

Lockerbie Academy received £2,000 funding from Magnox Ltd Chapelcross to develop an innovative and novel approach to teaching mechanics to pupils. Usually students are taught about forces, speed, acceleration, and the link between them, through ideas which often have little relevance to everyday life and experience.


Lockerbie Academy has designed their mechanics topic around a Road Safety Project, covering all the requirements of Curriculum for Excellence and providing an enquiring and active way to learn.  Pupils learn about speed using model cars and equipment, then from measurements taken calculate speed, velocity and use literacy and numeracy skills as well as Health and Well Being to look at the influence and impact of speed in road traffic accidents.

Students learn more about stopping distances using the state of the art reaction timer purchased from the generous donation provided by Magnox Ltd, Chapelcross. This enables students to have a better understanding of how long it would take a car to stop depending on speed and road conditions. A game called “Chicken Run” devised by a S3 Physics group and their teacher, Mrs Physics, provides a practical investigation and demonstrates to students in a safe environment the effects of using mobile phones and being distracted whilst driving.  Students will also be given information about the Highway Code and road signs and then look further into the physics behind the signs.

The picture shows Caitlin Carruthers, Aaran Stevenson, Chapelcross Communications Manager Sean Marshall, Caitlin Kerr, Inspector Neil Hewitson and Craig Johnstone along with some of the new resources used in the Road Safety project.

Dumfries and Galloway Constabulary’s Inspector Neil Hewitson has also been heavily involved in developing the materials and has provided the school with some additional PSHE (Personal Social Health and Education) literature for students. These materials deal with dangers of driving, being a passenger or pedestrian and effects such as alcohol and the use of mobile phones on driver’s abilities to function at the correct level. From this a further project developed, where a trained police crash test investigator came out to talk to the Higher Physics class on the use of Physics in crash test investigations and gave the students first hand examples of how the pieces of a crash are put together to determine the cause and blame of any incident. The students really gained so much from this experience.

Mrs Physics said “It has been really exciting putting this project together as it really focuses on the Physics and yet also gives us the opportunity to raise areas of real concern and addresses road safety, a major killer of young people aged 17-25. It has been wonderful to work with people from Magnox who have had a great background and focus on safety, as well as Dumfries and Galloway Police and Alan Jabez of motoring who also kindly provided resources for the project.  The project has the potential to be rolled out across other secondary schools in Dumfries & Galloway.”

Jill Callander, Communications Officer MAGNOX