Abstract:

This paper deals with the optimal velocity function for traffic flow, characterized by a rational function form. The critical headway is taken as the control parameter and used to establish the non-concave fundamental diagram. A new optimal velocity function considering stopping sight distance is proposed to describe human driving behavior in the driver-vehicle-road environment by rescaling the critical headway. Compared with other classical optimal velocity functions and related fundamental diagrams, the new function has advantages in explaining real traffic features such as scattering density-dependent flow data and variable highway capacity.

Key words: optimal velocity function; non-concave fundamental diagram; critical headway; stopping sight distance; driving behavior