  An intelligent speed advisory system can be used to recommend speed for
vehicles travelling in a given road network in cities. In this paper, we extend
our previous work where a distributed speed advisory system has been devised to
recommend an optimal consensus speed for a fleet of Internal Combustion Engine
Vehicles (ICEVs) in a highway scenario. In particular, we propose a novel
optimisation framework where the exact format of each vehicle's cost function
can be implicit, and our algorithm can be used to recommend multiple consensus
speeds for vehicles travelling on different lanes in an urban highway scenario.
Our studies show that the proposed scheme based on an improved whale
optimisation algorithm can effectively reduce CO2 emission generated from ICEVs
while providing different recommended speed options for groups of vehicles.
