  Quasi-one-dimensional bidirectional particle flow including the effect of
chemotaxis is investigated through a modification of the
John-Schadschneider-Chowdhury-Nishinari model. Specifically, we permit multiple
lanes to be shared by both directionally traveling particles. The relation
between particle density and flux is studied for several evaporation rates of
pheromone, and the following results are obtained: i) in the
low-particle-density range, the flux is enlarged by pheromone if the pheromone
evaporation rate is sufficiently low, ii) in the high particle-density range,
the flux is largest at a reasonably high evaporation rate and, iii) if the
evaporation rate is at the level intermediate between the above two cases, the
flux is kept small in the entire range of particle densities. The mechanism of
these behaviors is investigated by observing the spatial-temporal evolution of
particles and the average cluster size in the system.
