This assignment will investigate the physics and concepts behind Broadwater Road, Newnham Road intersection. As the council wants to put up speed limit signs on the approach of an intersection, a variety of scenarios will be investigated to conclude whether or not an increase, decrease of speed will be needed for this specific intersection. Developing and altering specific complications of intersections can either reduce of increase the risk of road crashes. As the yellow light also greatly impacts the number of crashes, as many driver can become restless or agitated if the yellow light is too quick; due to the attitude or underestimated assumptions many by drivers end up in the dilemma zone. This investigate report will specifically investigate the appropriate speed and time to break or react to a yellow light. Through these investigations, many principals, concepts and calculation will assist with the concluding this accusation. Principals used, mentioned and needed: Newton’s first law: Everybody stays motionless, or continues moving in a straight line, unless a force acts on it. “In the absence of an unbalanced force, an object in motion will maintain its state of motion. This is often called the law of inertia.” Inertia is experienced when riding in cars. Newton’s first look predicts the behaviour of stationary object and also moving objects. This diagram shows the difference between and moving and a stationary object. If the object is at rest, that it will state at rest but if an object is not at rest (moving) then only an external force may be able to stop it. In regard to a moving vehicle, to stop it from moving an unbalanced forced (braking) is applied to decrease speed until at totally rest. “The force of the roa... ... middle of paper ... ...s unable to either safely stop or safely proceed through the intersection at the onset of yellow.” (Administration, 2013) A result of drivers assuming that they will be able to clear the light, results in the vehicle not clearing the intersection. As the constant speed traveling (60km/h) for a car on Broadwater Newnham Road to clear the intersection, their stopping distance and reaction distance must be equal. This is because, if the car was approaching the intersection at 60km/h and the yellow light is at 3 seconds, then by the time it has reached 5 seconds the car wouldn’t have cleared the 30m intersection, it would have been positioned at……….m. Many drivers can become impatient, if the yellow light is too quick, this can cause mayhem, as it will result in an acceleration of speed whilst approaching the intersection and also an increase of dilemma zone faults.