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Braking distance refers to the distance a vehicle will travel from the point when its brakes are fully applied to when it comes to a complete stop. It is primarily affected by the original speed of the vehicle and the coefficient of friction between the tires and the road surface, [Note 1] and negligibly by the tires' rolling resistance and vehicle's air drag.
Thus, we can find the brake force of a vehicle through the formula: [1] = where: is the brake force; is the mass of the vehicle; is the initial velocity of the vehicle when the brakes were applied; is the distance traveled by the vehicle between when the brakes were applied until coming to a stop
The stopping distance s is also shortest when acceleration a is at the highest possible value compatible with road conditions: the equation s=ut + 1/2 at 2 makes s low when a is high and t is low. How much braking force to apply to each wheel depends both on ground conditions and on the balance of weight on the wheels at each instant in time.
d MT = braking distance, m (ft) V = design speed, km/h (mph) a = deceleration rate, m/s 2 (ft/s 2) Actual braking distances are affected by the vehicle type and condition, the incline of the road, the available traction, and numerous other factors. A deceleration rate of 3.4 m/s 2 (11.2 ft/s 2) is used to determine stopping sight distance. [6]
Should the driver fail to react, the Pre-Safe Brake triggers autonomous vehicle braking. Pedestrian detection is active up to about 72 km/h (45 mph), and can reduce collisions with pedestrians autonomously from an initial speed of up to 50 km/h (31 mph). [44] A radar sensor in the rear bumper monitors the traffic behind the vehicle.
Since kinetic energy increases quadratically with velocity (= /), an object moving at 10 m/s has 100 times as much energy as one of the same mass moving at 1 m/s, and consequently the theoretical braking distance, when braking at the traction limit, is up to 100 times as long. In practice, fast vehicles usually have significant air drag, and ...
Braking distance: feet feet meters safety: shorter is better Brake specific fuel consumption: lb/(hp·h) lb/(hp·h) g/(kW·h) economics, range lower is better traveled Distance: miles miles kilometers economy higher rating is better for vehicle longevity; lower elapsed is better for vehicle resale Drag coefficient (ratio) (ratio) (ratio)
In some cases, the brake balance may be adjusted to match the traction (grip) of the vehicle during braking, which usually means distributing a greater braking force to the front (for example 55/45). In other cases, it may be desirable for the brake balance to be the more similar at the front and rear (e.g. 50/50) for the tires to last longer ...