TP 123

Identifying capacity of the road infrastructure and proposals to eliminate congestion

Technical conditions “Identifying capacity of the road infrastructure and proposals to eliminate congestion” (TP 123) have been approved by the Ministry of Transport of the Czech Republic on 27.8.1999 under the reference no. 26567/99-120, with effect from 1.10.1999. TP 123 is divided into the parts A, B, C and D.
Part A (introduction) and part B (theoretical part) are in TP 123 focused on quality of traffic flow in terms of:

    1. Primarily, based on to the transport mode in the time of the survey on the operational section, three decisive operational statuses are applicable:

• Level of Service for mode 1 – no congestion – (according to the HCM LoS A ÷ D)
• Level of Service for mode 2 – unstable – (according to the HCM LoS E)
• Level of Service for mode 3 – congestion – (according to the HCM LoS F)

     2. Secondly, it is focused on distinguishing Level of Service of the mode 1 with relation to distinguishing conditions for individual driving lanes and driving directions in sections with more than 2 lanes for each direction. Conditions are characterised according to vehicle types for each driving lane at the time of the survey.

     3. Based on measurements, it was revealed also for our territory, that capacitive ability of road sections with two driving lanes and two driving directions (“two-lanes") do not exceed the total of 2800 personal vehicles/hour at both directions in ideal conditions. More details can be found in the article Fundamental Diagrams of the Equation of Continuity of Traffic Flow and Time Line – “Silniční obzor”.

Part C (congestions) and part D (models) are in TP 123 focused on issues of congestion initiation, definition and evaluation of congestion, derivation of congestion rate and modeling techniques for operating conditions in remote time horizons since the moment of statistical survey of operating conditions. Focus of these parts lies primarily in comprehensively outlined measures, which can contribute to reduction of congestion and which are semantically divided according to supply and demand. In terms of supply, measures are aimed at increasing quality of services of transport systems and, on the other hand, it describes a set of measures aimed at reducing demand, especially in the field of individual motor transport. 

The annexes of TP 123 include, in addition to bibliography, also an example of a Sample Plan for investigation "in situ" and the list of typical equipment suitable for detection of characteristics of the traffic flow. 

TP 123 is intended for road administrative authorities, administrators, investors, developers, transport authorities, transport engineers and all other interested parties and employees of departments of transport, departments of territorial planning, departments of development, or personnel affecting public transport services. However, TP does not replace standards for designing new or reconstructed sections of the road infrastructure. The survey can be conducted only at the time of the assignment or retrospectively. The set of practical proposals on how to face disproportions between permanent increase in performance of individual motor transport and capacity abilities of the road infrastructure, mainly in urban areas, must be supported by organised measurements prior to their successful implementation.