tell you sort of what actually happens inside the model but those you know rates of arrival of drivers and passengers so basically drivers enter at some rate lambda and when there's a drivers available ride requests arrive at some rate which depends on the number of available drivers that's what we computed earlier um if a driver is available the ride is served otherwise it's blocked rides lasts an exponential time with mean tau in the network model this sort of involves a random walk around the network so it's a little more