Counting Vehicles on MBBS Routes
A simple way to estimate human activity is to count the number of vehicles during a three-minute period at each stop. Usually you can count vehicles during the same three minutes you count birds. Any contraption moving on the ground with a motor counts as a vehicle!
If you extend the three minutes for counting birds to compensate for heavy traffic, do not make an extension for the traffic. Instead just count vehicles during the first three minutes -- whether or not the traffic is heavy!
If things are happening fast (lots of birds, lots of traffic), then the birds come first! Count the birds the best you can -- and estimate (guess) the number of vehicles the best you can.