Desired Speed

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Tangents The desired speed for a vehicle is calculated per the following equation.

$$DesiredSpeed (ft/s)=LinkFreeFlowSpeed (ft/s)\times DriverTypeDesiredSpeedMultiplier\times VehicleTypeDesiredSpeedProportion$$

The desired speed multiplier value (as a function of driver type) and desired speed proportion value (as a function of vehicle type) can be changed in the Settings. The link free-flow speed is coded by the user in the network setup.

Horizontal Curves Forthcoming.

$$ {V_{c,a}} = {\left( {\frac} \right)^{0.5}} $$

where: $${V_{c,a}}$$ = average curve speed (mi/h) $${V_{t,a}}$$ = average tangent speed (mi/h) $${R_p}$$ = travel path radius (replaced by curve radius in modified model) (ft) $${I_{tk}}$$ = indicator variable for heavy vehicles (1.0 if model is used to predict heavy vehicle speeds, 0.0 otherwise) e = superelevation rate (decimal)