  To alleviate traffic congestion, a variety of route guidance strategies has
been proposed for intelligent transportation systems. A number of the
strategies are proposed and investigated on a symmetric two-route traffic
system over the past decade. To evaluate the strategies in a more general
scenario, this paper conducts eight prevalent strategies on a asymmetric
two-route traffic network with different slowdown behaviors on alternative
routes. The results show that only mean velocity feedback strategy is able to
equalize travel time, i.e., approximate user optimality; while the others fail
due to incapability of establishing relations between the feedback parameters
and travel time. The paper helps better understand these strategies, and
suggests mean velocity feedback strategy if the authority intends to achieve
user optimality.
