Physics of Road Safety

In our modern world of today we slowly innovate more and more. However as we innovate we forget to advance and improve on our current inventions. One of these inventions is the automobile. One of the current problems facing the automobile is its safety on the road. With more people using automobiles, we should focus on solving these problems before looking towards the future of transportation. I will be discussing the factors which influence the road safety of automobiles.

Road safety is preventing the death or injury of people using the road. [1] Most deaths and injuries happen in road accidents, and to prevent these from happening, we must change the friction and texture of the road and adjust the tires so it’s compatible with the road. But for there to be a change to the roads construction will need to be done and some parts will not be new so setting up clear hazard signs may help prevent traffic accidents while improving road safety.

The Road

The Roads today around the world consist of asphalt, concrete, gravel and chip seal. All these types have factors that influence the friction with the car and it’s ability to slow down or speed up.

We’ll be looking first at gravel roads which are mostly set up in rural areas where not much traffic occurs. Because of the type of texture gravel contains. That being a form of stones. Cars will end up creating the road more bumpy and will shift and move the small rocks around due to there being minimal friction between the surface and the road. When the wheels of the car rotate around they shift the gravel as well creating potholes in the road. These make it unsafe to drive at fairly high speeds since the car can be thrown off balance if it encounters these potholes. In addition since most gravel roads are not connected and the road is made of loose gravel, the gravel can fly around and potentially damage parts of the car or even the tyres. [2] During rainy days these gravel roads become muddy and problematic to drive through. Strong control over the steering wheel will be be required as one would need to be watch out for eroded areas on the road and drainage ditches for larger cars, as they face the problem of potentially overturning due to their high centre of gravity. [2] To prevent the likelihood of these accidents happening Hazard signs telling one to look out at the road will have to be set up to alert drivers that they could encounter such problems if they pass through here, if improvement of the road is not possible.

The asphalt roads are much better than the gravel roads. They are not crushed rocks laid out on a road but a chemical mixture that has a smooth surface. Asphalt is mostly laid out on gravel roads to improve its durability. The bitumen allows the asphalt to endure significant plastic deformation. [12] Because of the asphalt being so compact it is unable to erode as easily as gravel and will suffer minimal fatigue from heavy cars passing on it. This will make driving more comfortable and safer than driving on a gravel road.

Another type of Asphalt is Chip seal. This is used for pavements and streets in rural and minor traffic areas. Chip seal is made from combining layers of asphalt with aggregate. [4] Chip seal roads aren’t particularly safe to drive on at fast speeds. Because of the crushed stone that may be sometimes left behind while applying the chipseal on the road they can chip of the paint on some cars and cause loss of control for smaller vehicles. [4]

Concrete is considerably popular in most countries around the world and is what most are made of nowadays. Concrete is made from mixing cement, sand and water. Concrete can sometimes have a smooth surface depending with what it’s mixed with. Compared to asphalt, concrete is resistant to weather conditions, lasts longer but doesn’t provide better traction.

The Tyre

There are different types of tyres but they all require traction to be able to move, stop and turn on the road. There is Dry Traction and Wet Traction. Tyres have different tread patterns that suit for better traction on dry or wet surfaces. [5] Adjusting tread patterns to increase the traction to the surface of a road may also increase in reducing the braking distance and increase road safety. By using only one type of road it will be easier to produce more tyres that have a strong traction to that specific road and the only worry would be whether the traction is suitable for dry or wet surfaces. This can easily be determined by the climate and condition of some parts of a road (floodable or not) and when the time comes the tyres can be changed to provide traction on wet surfaces.

Braking Distance

The most popular and common roads are concrete so we’ll use that as the road for our solution. Concrete roads don’t provide much traction due to their smooth surface however they are resistant to weather conditions and last longer so we won’t have to worry much apart from the tyres. Since the road isn’t affected by the weather we can expect that there won’t be completely wet surface unless flooded. So we can focus on having our tyres maintain a dry traction to the surface although this may vary for different countries which have different climates. Most common tyres are ones with symmetrical tread patterns but we’ll be using asymmetrical tread patterns as these benefit us more since it offers greater contact area giving us more stability on a dry surface which is want we want on a concrete road. [7] [8]

Since we know what tyre and road we will be using we can now calculate the braking distance this will give us. The formula we have for Kinetic Energy is . [11] m being the mass of the car and v being the velocity at the start of breaking. The average mass of a car is 1500 kg and in this case our velocity is going to 5ms/s. [5] Our equation should then look something like this Then leaving us with and finally . But to find the braking distance we need to find the Work done by the force of the break to give us an equation for the distance. The formulae for Work done is . [11] being the coefficient of friction while m is the mass of the car, g is the gravity of the earth and d is the stopping distance. But to solve this equation we need to figure out the stopping distance.

The formula for the stopping distance is . [11] If we substitute our numbers then we end up with . For this equation is the coefficient of friction for concrete. [10] If we substitute this in for our second formulae then we will end up with which will be but the answer we get is not equal because So this means that the car will not come to a complete halt after braking for 1.59 metres. However the car will come to a complete stop after 1.6 metres because the since which would mean that the car will come to a halt between 10 cm after the car has passed 1.59 metres while braking.

The Impacts

Impacts of Implementing this solution into society will be a huge change and may need to involve a large amount of investment in the construction project. This may benefit the local economy by providing more jobs to people but the cost of the project may be to overwhelming for a single country to pay on it’s own and will have to borrow money from other countries. This may cause the country to go into debt despite partially benefitting the local economy. Even though tyre manufacturers can now start producing 1 type of tyre (depending on where they are manufacturing to( can easily be invested in and demands of their product will cause a rise in the economy.

For the locals creating a huge construction project that will make roads unusable until they are finished constructing may be a bother and people will not be willing to have their roads unusable if they are a car user and want use their car to travel around. This may spark protests and can escalate into violent riots since the reactions of people may vary from country to country depending on their situations.

Politicians may use this solution to convince and win the favour of the people by granting them safer roads and cars. This may influence peoples votes but creation requires destruction and our environment could be damaged by the large scale construction project and cause animals to lose their habitat since they need to first gather the resources to make concrete, use the energy required to make concrete, and finally lay out the concrete all of these may be done by non environmentally friendly machines which cause damage to it’s surroundings through different means (eg. pollution).

Conclusion

To be able to reduce all the negative impacts of the solution we came up with we can limit the use to only when a country decides to construct / repair a road and when manufacturers create new cars. To make the impact even smaller and more environmentally friendly we can only allow the use of our solution in major cities of a country and not on every road although this will limit our general goal of our solution. But it will increase your safety on the road.

Bibliography

[1](http://en.wikipedia.org/wiki/Road_traffic_safety).

[2]http://en.wikipedia.org/wiki/Gravel_road

[3]http://www.innovateus.net/innopedia/what-are-roads-made-out

[4]http://en.wikipedia.org/wiki/Chipseal

[5]http://www.gcse.com/fm/braking.htm

[6]http://en.wikipedia.org/wiki/Tread

[7]http://www.tirerack.com/tires/tiretech/techpage.jsp?techid=180

[8]http://www.ctyres.co.uk/tyre_info/tyretreaddesign.html

[9]http://www.answers.com/Q/What_is_the_mass_of_an_average_car

[10]http://hypertextbook.com/facts/2006/MatthewMichaels.shtml

[11]http://en.wikipedia.org/wiki/Braking_distance

[12]http://en.wikipedia.org/wiki/Road_surface