EEM1 (road infrastructure) Appendix 3 - Travel time estimation procedures
Summary
Travel times shall be estimated according to the procedures in this appendix. Definitions for classifying traffic data and default traffic data values are provided in appendix A2. Where a specific procedure is not given, the travel time shall be determined according to a recognised procedure compatible with the manuals and procedures referred to in this appendix.
- A3.1 - Travel time estimation procedures
- A3.2 - The stages for estimating travel time
- A3.3 - Determining traffic volumes
- A3.4 - Calculating free speed travel time
- A3.5 - Determining the free speed of multilane roads
- A3.6 - Determining the free speed of two-lane rural roads
- A3.7 - Determining the free speed of other urban roads
- A3.8 - Determining the capacity of road sections
- A3.9 - Determining the capacity of motorways
- A3.10 - Determining the capacity of multilane roads
- A3.11- Determining the capacity of two-lane rural roads
- A3.12 - Determining whether vehicle interactions are significant
- A3.13 - Types of delay
- A3.14 - Average peak interval traffic intensity
- A3.15 - Determining the peak interval
- A3.16 - Calculating the average peak interval traffic intensity
- A3.17 - Calculating the volume to capacity ratio
- A3.18 - Calculating the additional travel time
- A3.19 - Calculating bottleneck delay
- A3.20 - Determining whether to consider peak spreading
- A3.21 - Determining the additional travel time resulting from speed change cycles
- A3.22 - Calculating the time period total average travel time
- A3.23 - Traffic signals
- A3.24 - Priority intersections
- A3.25 - Roundabouts
- A3.26 - References
A3.1 - Travel time estimation procedures
Introduction
Travel times shall be estimated according to the procedures in this appendix. Definitions for classifying traffic data and default traffic data values are provided in appendix A2. Where a specific procedure is not given, the travel time shall be determined according to a recognised procedure compatible with the manuals and procedures referred to in this appendix.
The methods are capable of application by hand, spreadsheet and within transportation models. The methodology gives a reasonable approximation for travel time without having to analyse dynamic queuing situations. More precise methods are not precluded.
Use of measured data
Wherever practical, measured data shall be used in preference to the default values given in the tables.
Basis of methodology
The procedures for road sections are based on and are consistent with the Highway capacity manual (HCM)1.
The procedures for intersections are drawn from Akcelik and Rouphail2, ARRB internal report 367-13, ARRB research report 1234, Kimber and Hollis5 and Austroads Guide to traffic engineering practice, part 6 - roundabouts.
Transportation models
When a transportation model is used for project analysis, the model shall have been satisfactorily validated on both traffic volumes and travel times. Checklists for validating transportation models are provided in worksheet 8 of the full procedures.
It is necessary that the travel times used by the model to derive the flows must be consistent with the travel times estimated by using this appendix during evaluation. To adhere to this it is suggested that the functions implied by the procedures in this appendix be used as a starting point, and modified as necessary to get a satisfactory validation.
