Braking delay

The braking deceleration , also negative acceleration , indicates how much a body is braked. The braking deceleration is given in the unit m / s².

The mean braking deceleration  a of braking from speed  v to zero with braking distance  s is:

${\displaystyle a=-{\frac {v^{2}}{2s}}}$

The mean deceleration of braking from speed  v ₂ to speed  v ₁ with braking distance  s is:

${\displaystyle a=-{\frac {1}{s}}{\biggl (}{\frac {v_{2}^{2}}{2}}-{\frac {v_{1}^{2}}{2}}{\biggr )}}$

Example: starting speed v ₂ = 20 m / s, remaining speed v ₁ = 10 m / s, braking distance s = 100 m:

${\displaystyle a={\frac {(20\,\mathrm {m/s} )^{2}-(10\,\mathrm {m/s} )^{2}}{2\cdot 100\,\mathrm {m} }}=1{,}5\,\mathrm {m/s} ^{2}}$

The braking delay is z. Sometimes also given in fractions or multiples of the acceleration due to gravity . ${\displaystyle g}$

meaning

The braking deceleration is an important criterion for the safety of vehicles and ships and should be as high as possible. When spacecraft re- enters, however, it must not exceed certain values ​​depending on the payload and thermal load.

literature

• Heinz Burg, Andreas Moser (ed.): Handbook of traffic accident reconstruction. Accident recording - vehicle dynamics - simulation, 3rd edition, Springer Verlag, Berlin / Heidelberg 2017, ISBN 978-3-658-16142-2 .
• Horst Bauer: Driving safety systems. 2nd edition, Friedrich Vieweg & Sohn Verlagsgesellschaft mbH, Braunschweig 1998, ISBN 978-3-322-91815-4 .
• Diedrich Lütjen, Manfred Müller: Automobile computing. BG Teubner Verlag, Stuttgart 1984, ISBN 978-3-519-06721-4 .

Web links

• List of typical braking delays of vehicles on different lanes
• Calculation of the stopping distance (accessed on November 16, 2017)
• Braking delays and induction of falls of motorcycles (accessed November 16, 2017)
• Brake deceleration and extrapolation (accessed on November 16, 2017)
• Interactive table that can be used to determine the initial speed, the brake track length or the final speed (collision speed) of a vehicle depending on the deceleration and braking threshold time - via juratexte.de .