## Stopping distance calculator pdf

The calculator below estimates the stopping distance for a well maintained car with an alert driver on a dry road. Obviously actual stopping distances will vary considerably depending on condition of the road and car as well as the alertness of the driver. You can use this stopping distance calculator to find out how far your car travels in that time, depending on your speed, the slope of the road, and weather conditions. In this text, we will clarify the difference between the stopping distance and the braking inbetatest.website: Bogna Haponiuk. The Overall Stopping Distances are DOUBLED (x 2)for wet roads and multiplied by TEN (x 10)for snow and icy conditions. Below is a chart showing a system for working out the Overall Stopping Distancein feet. Example: 30mph x 21⁄ 2 = 75ft Thinking Distancein feet is the same as the speed travelling at. Example: 30mph = 30ft think distance. a constant braking force, we can see that the dependence of the stopping distance on the initial speed should be quadratic. We should also point out the actual values of the car stopping distances at various initial speeds. We should warn students that we have measured net stopping distances disregarding the driver’s reaction time. Stopping Distance (RSD) friction material. In addition to meeting the FMVSS reduced stopping distance requirements for new vehicles, Meritor friction materials have been re-engineered to offer improved lining life compared to older-generation Meritor materials. That’s a better idea that delivers the braking results ﬂeets and end users want. The human perception distance is the distance a vehicle travels while the driver is identifying a hazard and deciding to slow down and stop the vehicle. The results of research 1in which the coefficient of friction was determined by means of measuring deceleration, identified that the anti-lock braking system ABS influenced distane coefficient of friction: struts2 tiles libraries s increases with velocity increasing when using ABS and decreases with increasing velocity when ABS is not used. System of Pulleys — Mechanical Advantage Calculator. The calculator can also determine the skid pre-braking speed from a known braking distance skid mark length taking into account the road conditions. In pneumatic brakes, air needs to flow through brake lines and this takes time. Skid Pre-braking Speed Stopping distance calculator pdf Input. more information restorable 1941 ford cars Calculating Train Braking Distance David Barney, David Haley and George Nikandros stopping distance, i.e. the product of the train’s mass (m), the train’s acceleration rate (a) (deceleration is negative To calculate braking distances it is therefore a matter ofCited by: STOPDIST Train Braking Distance Calculation Tool User Guide ESI Description of STOPDIST This document is uncontrolled when printed. Version Number: Date Reviewed: 19 June Page 6 of 17 Train Speed, Times and Coordinates Entries To calculate the braking distance for each type of train the following must be entered. Stopping (Braking) Distance Calculator Common questions that arise in traffic accident reconstructions are "What was the vehicle's initial speed given a skid length?" and "What distance is required to stop from this speed?". You will be able to answer these questions by simply entering the road surface type, units, and speed or distance below.

Random converter. The calculator determines the stopping distance from the moment the driver detected a hazard to the moment of the complete stop as well as other parameters associated with this event that include human perception and reaction time and distance, deceleration, braking time and distance, and other values.

The calculator can also determine the skid pre-braking speed from a known braking distance skid mark length taking into account the road conditions. As with all other calculators, please do not use it in any legal proceedings.

The stopping distance is the distance a vehicle travels from the time a driver sees a hazard, takes a decision to stop a vehicle, presses on the brake pedal until the vehicle comes to a complete stop. This distance is the sum of several distances that the car travels while the driver makes a decision, the brakes are activated and the vehicle slows down until it stops. The stopping distance s stop is determined using the following formula:.

These distances are discussed below. The human perception distance is the distance a vehicle travels while the driver is identifying a hazard and deciding to slow down and stop the vehicle. It is calculated using the following formula. The human reaction distance is the distance a vehicle travels while the driver is executing a decision to stop the vehicle after they recognized a danger. It is determined using the following formula. The brake lag distance depends on the type of brakes used in the vehicle.

Hydraulic brakes are used on almost all cars and light trucks. Air brakes are used on almost all commercial trucks. The air brake lag is approximately 0. The total brake delay is measured as the time from the moment the brake pedal is depressed to the moment at which deceleration has reached steady-state. It consists of the lag time in the brake system and the deceleration rising time.

For pneumatic brakes, the total brake delay varies from 0. In pneumatic brakes, air needs to flow through brake lines and this takes time. Hydraulic brakes, on the other hand, act almost instantly, two to five times faster than the air brake. To simplify our calculations, we will assume that the vehicle is moving with constant acceleration or deceleration, which is determined using the following formula derived from the equation of accelerated decelerated motion:. The braking distance is the distance a vehicle travels from the moment when its brakes are fully applied to the moment when it comes to a complete stop.

This distance depends on the pre-braking speed of the vehicle and the coefficient of friction between the tires and the road surface. In this calculator, we will not consider other factors with negligible influence such as rolling drag of the tires or air drag. The results of research 1 , in which the coefficient of friction was determined by means of measuring deceleration, identified that the anti-lock braking system ABS influenced the coefficient of friction: it increases with velocity increasing when using ABS and decreases with increasing velocity when ABS is not used.

This research also confirmed that the coefficient of friction between the tires and the road is affected by temperature and rainfall.

By definition, the coefficient of friction is defined as the ratio of force of friction to the normal force:. The normal force acting on an object is defined as the component of a contact force that is perpendicular to the contact surface of the object. For a simple case when an object is placed on a flat horizontal surface, the normal force is just its weight:.

In a more complex case where an object rests on an inclined surface, the normal force is calculated as. In this case, the normal force is smaller than the object weight. We will consider this case later. We know from the course of elementary physics that for the decelerated motion with constant deceleration if the final velocity equals zero, then the braking distance s br is determined using the following equation:.

The theoretical braking distance can be found if we determine the work required to dissipate the kinetic energy of the vehicle.

If a vehicle moving with the speed v decelerates to a complete stop, the braking work W b required to fully dissipate its kinetic energy E k will be equal to this energy:. The speed of the vehicle before braking is the most important factor influencing the stopping distance.

Other factors such as recognition response time of the driver, the performance of the vehicle braking system, the road conditions are less important components in the stopping distance. We know from the course of elementary physics that the average speed of accelerated motion at constant acceleration is equal to the half-sum of the initial and final speed:. For simplification, we consider only two forces acting on a vehicle on an inclined road.

They are the vehicle weight and the friction force. The vehicle moving with the initial speed is decelerating when the friction force acting parallel to the surface of the road is larger than the pulling component of the vehicle weight, which is also parallel to the slope. If the initial velocity of the vehicle is zero, it is not moving in this situation provided that the angle of inclination is less than the critical angle we will talk about the critical angle later.

When the force of gravity F g pulls the vehicle down, for force of friction F fr resists this movement. For the vehicle being able to stop, the force of friction must exceed the downhill pulling component F gd of the force of gravity. At the same time, if the friction force is smaller than the pulling component of the vehicle weight, the vehicle will be moving downward with constant acceleration and its brakes will not be able to stop it.

This can happen if the angle of inclination or the road grade is too high or the coefficient of friction is too low remember how a car with ordinary tires behaves on an icy slope! As we have already mentioned, F total must point upwards, otherwise, the vehicle that is moving downhill cannot be stopped. The last two formulas are used in our calculator. The grade also called slope or gradient of a road is the tangent of the angle of its surface to the horizontal.

It is calculated as a ratio of rise vertical distance or change in elevation of the slope to run horizontal distance. By definition of the slope grade, driving uphill means climbing a positive grade slope and driving downhill means descending along a negative grade slope where a rise actually means drop.

For example, a rise of 15 meters per meters of horizontal movement corresponds to a slope of 0. In this calculator we use the grade in percentage, which is determined as.

When the inclination angle of the road exceeds a certain value called a critical angle, the vehicle moving downhill cannot be stopped using its braking system because the friction force acting on it becomes less than the rolling component of the vehicle weight. This critical angle can be found from the following condition:. From this formula, we can derive the critical angle at which the vehicle will not stop at the given coefficient of friction:.

An example of using the formula for braking distance. Calculate the braking distance. For our calculations, we will use the formulas derived above. Simple Machine Mechanical Advantage Calculator. Wheel and Axle Mechanical Advantage Calculator. 