One of the basic parameters which describes road traffic is Annual Average Daily Traffic (AADT). Its accurate determination is possible only on the basis of data from the continuous measurement of traffic. However, such data for most road sections is unavailable, so AADT must be determined on the basis of short periods of random measurements. This article presents different methods of estimating AADT on the basis of daily traffic (VOL), and includes the traditional Factor Approach, developed Regression Models and Artificial Neural Network models. As explanatory variables, quantitative variables (VOL and the share of heavy vehicles) as well as qualitative variables (day of the week, month, level of AADT, the cross-section, road class, nature of the area, spatial linking, region of Poland and the nature of traffic patterns) were used. Based on comparisons of the presented methods, the Factor Approach was identified as the most useful.
The author investigated traffic flow quality on a new 2+1 long road bypass with an exceptionally high share of heavy vehicles in order to assess rational limits of heavy vehicle shares in traffic flow, dependent on the length of the 2+1 road and the number of passing segments in each direction. This paper presents the results of traffic flow quality analyses through the use of empirical and simulation methods for a single 2+1 road segment with additional passing lanes, as well as for the study of the entire section of the bypass – 2+1 road. Variables include analysis of travel speed distribution, platoon traffic, and amount of passing maneuvers. Results show that large passing demands lead to very high speeds (over 100 km/h) on segments with additional passing lanes. The conclusions include remarks related to the use and operation of 2+1 cross-sections with high shares of heavy vehicles.
The Traffic Flow Description (TFD) option of the IP protocol is an experimental option, designed by the Authors and described by the IETF’s Internet Draft. This option was intended for signalling for QoS purposes. Knowledge about forthcoming traffic (such as the amount of data that will be transferred in a given period of time) is conveyed in the fields of the option between end-systems. TFD-capable routers on a path (or a multicast tree) between the sender and receiver(s) are able to read this information, process it and use it for bandwidth allocation. If the time horizons are short enough, bandwidth allocation will be performed dynamically. In the paper a performance evaluation of an HD video transmission QoS assured with the use of the TFD option is presented. The analysis was made for a variable number of video streams and a variable number of TCP flows that compete with the videos for the bandwidth of the shared link. Results show that the dynamic bandwidth allocation using the TFD option better assures the QoS of HD video than the classic solution, based on the RSVP protocol.
The sound radiation from vehicles travelling on the city roads with T junction was considered. The wind effect on acoustic field was taken into account. The solution of this problem was found with the help of the integral Fourier transforms and stationary phase method as the superposition of solutions for the cases of vehicles moving along the straight roads and roads with right-angle bend. As an example, the numerical analysis of traffic noise characteristics was carried out for the T junction city road on one of streets in the town of Łodź (Poland).