  A nonparametric fuel consumption model is developed and used for eco-routing
algorithm development in this paper. Six months of driving information from the
city of Ann Arbor is collected from 2,000 vehicles. The road grade information
from more than 1,100 km of road network is modeled and the software Autonomie
is used to calculate fuel consumption for all trips on the road network. Four
different routing strategies including shortest distance, shortest time,
eco-routing, and travel-time-constrained eco-routing are compared. The results
show that eco-routing can reduce fuel consumption, but may increase travel
time. A travel-time-constrained eco-routing algorithm is developed to keep most
the fuel saving benefit while incurring very little increase in travel time.
