I am using the Googleway package and I don't have any difference between "pessimistic", "optimistic" & best_guess" as well as results are similar when mentioning "driving", "walking" or "cycling" modes. Maybe I am wrong in my code:
google_distance(origins = "place Viarme 44000 nantes",
destinations = "rue de strasbourg Nantes",
mode="driving",
departure_time=heure_dep,
traffic_model='best_guess',
key = key,
simplify = T)
google_distance(origins = "place Viarme 44000 nantes",
destinations = "rue de strasbourg Nantes",
mode="bicycling",
departure_time=heure_dep,
traffic_model='best_guess',
key = key,
simplify = T)
Thanks