3Traffic operations level of service for roadworks sites#

3.1Purpose#

This section provides guidance for determining the appropriate traffic operations Level of Service (LOS) to be maintained through roadworks sites. LOS is defined in Austroads Guide to Traffic Management Part 3 This guidance is to be applied in the assessment of alternative construction and traffic management schemes on traffic operations.

3.2Background#

Most roadworks schemes invariably require a degree of interruption to the normal flow of traffic on a road. The acceptable level of impact is dependent on a range of factors including the urgency of the works, the scale of the works, the advance notice provided to the community and the availability of alternative routes or modes of transport.

In developing a Traffic Guidance Scheme, the primary objective is to ensure the safety of road workers and road users. The secondary objective is to balance the:

• safe and convenient movement of traffic (community costs), and
• construction and traffic management costs (project costs).

These elements must be carefully assessed to ensure that the most appropriate balance is found to ensure that cost effective solutions are being applied.

Examples of the inefficient application of a Traffic Guidance Scheme can include:

• The traffic operations principles behind a Traffic Guidance Scheme are based purely on maintaining traffic flow. In these cases, the minimum number of lanes to be retained in each direction on each road is usually defined. This can result in constraints on the construction process which may lead to the inefficient sequencing and conduct of the works which can potentially increase the project costs.
• A minimum Level of Service is specified based on maintaining existing traffic conditions. This can severely affect the times at which construction activity can be undertaken, which can result in an associated increase in project costs.

Alternatively, the most effective construction practice may result in extensive delays / detours to traffic with substantial community impact. In these cases, delays at roadworks sites can be a source of frustration for drivers which may potentially lead to an increased risk for road users and road workers This note, therefore, provides some guidance on determining the appropriate balance between traffic operations and construction process.

3.3Discussion#

The following principles for roadworks LOS shall apply:

1. 1.In the following cases, the community cost will be considered to be NIL and the most efficient construction process which complies with these LOS parameters should be applied:
2. a.If the existing LOS on the road is A, B or C, then a traffic management treatment which delivers no worse than LOS D.
3. b.If the existing LOS on the road is D, then a traffic management treatment which delivers no worse than LOS E.
4. c.If the existing LOS on the road is E or F, then a traffic management treatment which maintains the existing traffic operational performance.
5. 2.An assessment of the community cost against the construction cost will be undertaken in all other circumstances
6. 3.Travel time costs:
7. a.Travel time costs are to be determined using the approach documented within Clause 3.2 of the Austroads Guide to Project Evaluation Part 4: Project Evaluation Data, 2012.
8. b.Private travel time cost is adopted for a single occupant (A$13.17/hour) which, as per the Austroads Guide, was assumed to be 40% of average hourly earnings (A$32.93, as per quarter ending 31st May 2010).
9. c.Business travel time for cars is assumed to be the average hourly earnings.
10. d.These figures need to be increased by CPI to current day figures.
11. 4.Traffic management costs and project costs should be provided by the contractor undertaking the works