Abstract
A theoretical analysis of the dynamics of perspective changes during the approach of simple horizontal curves reveals that the three objective characteristics: distance to the start of the curved section, radius and deflection angle are represented in the dynamic perspective in a complex way. The main findings point to the importance of deflection angle for the judgment of curvature- suggesting that radius should not be based solely on design speed, - and to the effect of distance to the start of the curved section on the possibilities for discriminating between curves of different radii.