Trafficlike collective movement of ants on trails: absence of jammed phase

We report experimental results on unidirectional traffic-like collective movement of ants on trails. Our work is primarily motivated by fundamental questions on the collective spatio-temporal organization in systems of interacting motile constituents driven far from equilibrium. Making use of the analogies with vehicular traffic, we analyze our experimental data for the spatio-temporal organisation of the ants on the trail. From this analysis, we extract the flow-density relation as well as the distributions of velocities of the ants and distance-headways. Some of our observations are consistent with our earlier models of ant-traffic, which are appropriate extensions of the asymmetric simple exclusion process (ASEP). In sharp contrast to highway traffic and most other transport processes, the average velocity of the ants is almost independent of their density on the trail. Consequently, no jammed phase is observed.