  This paper presents a calibration method for the speed-flow model of the HCM
2016 for freeways and multilane highways allied to temporal analysis of traffic
stream. The proposed method was developed using a sample of more than one
million observations collected by 23 traffic sensors on four highways in the
state of S{\~a}o Paulo. The method is structured on Bayesian inference and
provided for each model parameters a probability distribution function. The
free-flow speed and capacity presented a probability density function that
approximates a Normal distribution. The segment in which the speed of traffic
stream remain constant with the increase of the traffic flow is lower than
described in HCM 2016, being in some cases close to zero. Along with the
proposed calibration method an analysis of temporal variation is performed
which shows a significant variation in traffic behavior for different periods.
The free-flow speed, capacity and breakpoint distributions obtained through
monthly and annual calibration were considered equal by means of
Kolmogorov-Smirnov test, different for the model calibration coefficient.
