  Vehicle-to-infrastructure (V2I) communication is becoming indispensable for
successful roll-out of connected and autonomous vehicles (CAVs). While
increasing the CAVs' speed improves the average CAV traffic flow, it increases
communication handoffs (HOs) thus reducing wireless data rates. Furthermore,
unplanned density of active base-stations (BSs) may result in severe
interference which negatively impacts CAV data rate. In this letter, we first
characterize macroscopic traffic flow by considering log-normal distribution of
the spacing between CAVs. We then derive novel closed-form expressions for the
exact HO-aware rate outage probability and ergodic capacity in a large-scale
network with interference. Then, we formulate a traffic flow maximization
problem to optimize the speed of CAVs and deployment density of BSs with
HO-aware rate constraints and collision avoidance constraints. Our numerical
results validate the closed-form analytical expressions, extract useful
insights about the optimal speed and BS density, and highlight the key
trade-offs between the HO-aware data rates and CAV traffic flow.
