A methodology is presented for calibrating the car-following model proposed by Gipps. This calibration procedure is concerned with steadystate conditions. A steady state occurs when the leader and follower vehicles travel at similar and near-constant speeds, maintaining similar space headways between each other. Steady-state calibration is important because it determines roadway capacity, speed at capacity, and jam density (spatial extent of queues when fully stopped). The calibration process allows the identification of adequate values for deceleration rates, b (maximum deceleration rate the driver is willing to use), b'. (the maximum deceleration rate estimated for the leader), and driver reaction time (T). Two different behavioral assumptions were developed concerning the deceleration rates: b equal to b' and b different from b'. The first hypothesis assumes that the leader will be as aggressive as the follower. The second assumes that the driver considers the leader to have a different maximum deceleration rate. The results are presented in tables and graphs that correlate the car-following parameters to the fundamental traffic stream variables for the different behavioral assumptions. The procedures are then tested on sample field data to demonstrate the adequacy of the calibration procedures.