Worksheets A7: Vehicle passing options

Worksheets A7: Vehicle passing options

Explanation sheet for passing lane strategy analysis

This worksheet is used in the analysis of passing lane strategies. The worksheet is completed as follows.

1 Project option Enter the project option.
2 Initial analysis year Enter the initial analysis year for the strategy.
3 Road section Enter the name and simple description of the road section under consideration, see appendix A7.3.
4 Sub-section For each-subsection (see appendix A7.3) enter:
  • Sub-section name.
  • Start description (route position if applicable).
  • Finish description (route position if applicable).
  • Sub-section length.
  • Traffic growth rate (as percentage of analysis year).
5 AADT Enter the AADT for the analysis year and each five year increments up to 20 years.

Worksheet A7.1 (49.5 kb)

Example for worksheet A7.1 (27.6 kb)

Explanation sheet for passing lane strategy analysis summary

This worksheet is used in the analysis of passing lane strategies. The worksheet is completed as follows.

1 Project option Enter the project option.
2 Initial analysis year Enter the initial analysis year for the strategy.
3 Road section Enter the name and simple description of the road section under consideration (see appendix A7.3).
For each sub-section enter:
4 Generalised gradient The sum of the absolute rises and falls, expressed in metres/km.
5 Generalised curvature The sum of the horizontal deviation expressed as degrees of curvature per km.
6 Terrain type Using (4) and (5) to determine the terrain type from table A7.5.
7 Percent PSD Enter the percent of road with safe passing sight distance.
8 Method Identify the method used to determine the proportion of road with passing sight distance.
9 BCR and spacing For the given terrain type (6), percent of road with safe passing sight distance (7), and the AADT (worksheet A7.1) determine from figures A7.3 to A7.6 the benefit cost ratio assuming a 2% traffic growth. Use the appropriate factor from table A7.7 to adjust the benefit cost ratio for traffic growth. Repeat this procedure to determine the optimal passing lane strategy in five year increments.

The optimal strategy for any particular analysis year is determined by considering in turn the BCR for each spacing alternative, beginning with the closest passing lane spacing strategy. If, when all other aspects of the strategy are taken into account, the BCR for the closest spacing is not sufficient to obtain funding (refer Land Transport NZ's National Land Transport Programme) consider the next most frequent passing lane strategy.

Worksheet A7.2 (62.0 kb)

Example for worksheet A7.2 (38.9 kb)

Explanation sheet for individual passing lane analysis

This worksheet is used for the analysis of individual passing lanes within an overall strategy. The worksheet is completed as follows:

1 Costs Enter costs for the do minimum and option.
2 Data
  • Enter the passing lane spacing from the passing lane strategy. If an isolated passing lane enter 20 km.
  • Enter the terrain type (from worksheet A7.2 or table A7.5).
  • Enter the AADT for the analysis year.
  • Enter traffic growth (expressed as a proportion of the time zero AADT).
  • Enter the percentage of road with safe passing sight distance.
  • Enter the length of the passing lane excluding tapers.
  • Enter the proportion of heavy vehicles (the sum of the proportions of MCV, HCVI and HCVII).
  • Enter the coefficient of variation of vehicle speeds if available. If not enter the default value of 13.5%.
3 Calculations
  • Determine the travel time and vehicle operating cost savings from figure A7.7 and multiply with the appropriate factors from table A7.9 and table A12.2.
  • Determine the driver frustration benefits from figure A7.8 and multiply with the appropriate factors from table A7.9 and table A12.2.
  • Calculate the base value of road user benefits.
  • Enter the passing lane length adjustment from table A7.11.
  • Adjust the base road user benefits.
  • Adjust for variations in the proportion of heavy vehicles at the site.
  • Adjust for variations in the distribution of vehicle speeds at the site.
  • Determine the accident cost savings from figures A7.9 to A7.12. Multiply by the appropriate factor from table A7.12 and table A12.2. Alternatively, if appropriate, use accident by accident analysis.
  • Calculate the total benefits.
  • Calculate the total costs.
4 BCR Calculate the benefit cost ratio.

Worksheet A7.3 (53.5 kb)

Example for worksheet A7.3 (29.5 kb)