Decision Sight Distance

Written by Jerry Ratzlaff on . Posted in Civil Engineering

stopping distance 1Decision sight distance, abbreviated as DSD, is the distance required for a driver to detect an unexpected obstacle or problem and react approperately.


Decision Sight Distance formula

\(\large{ DSD =  1.47 \; V \; t   }\)   


 Units English Metric
\(\large{ DSD }\) = decision sight distance \(\large{ft}\) \(\large{m}\)
\(\large{ V }\) = design speed \(\large{\frac{ft}{sec}}\) \(\large{\frac{m}{sec}}\)
\(\large{ t }\) = total time for the maneuver (reaction time + maneuver time) \(\large{sec}\) \(\large{s}\)


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Tags: Equations for Transportation Equations for Surveying