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Chapter
4 Evaluation and Monitoring Procedures
| 4.1 Introduction
4.2 The implementation of the speed revision program 4.3 Procedures for identifying roads 4.4 Procedures for ongoing evaluation |
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This chapter examines the specific terms of reference relating to:
The focus of this chapter is on whether the necessary work has been done (or is planned to be done) and that appropriate procedures and managerial arrangements are in place to ensure that the effects of the speed revision program are (and will be) adequately monitored and evaluated.
The Committee is interested in ensuring that both:
The speed revision program was guided and co-ordinated by the Speed Management Policy Committee and the physical implementation was carried out by VicRoads and municipal councils. The revision has now been completed throughout Victoria.
The Committee notes however that the speed revision program has not included a general urban speed limit of less than 60 km/h (as was recommended by the Social Development Committee and supported initially by the Government) and this is discussed in Chapter Five. The Committee also understands that VicRoads, at the request of the Minister for Roads and Ports are currently conducting investigations into:
Further details of these investigations are also given in Chapter Five.
The VicRoads submission said that the need to revise speed limits on particular roads may arise because of:
The Victoria Police and the Royal Automobile Club of Victoria (RACV) submissions both mentioned the use of summaries of speed camera information which assisted in the ongoing monitoring and review of travel speeds and traffic offences to identify roads where speed limits needed to be revised. Neither submission, nor that of VicRoads, mentioned the use of accident information as an initial input. It would appear that accident information came into the process at a later time when the VLIMITS expert computer system was being used for a particular section of road.
The responsibility for identifying and implementing any speed limit changes in Victoria lies with VicRoads and the techniques and standards used are described in the Speed Zoning Guidelines Section of the VicRoads Traffic Engineering Manual. [3] The actual work is undertaken by the regional operations areas of VicRoads. Sections of road requiring revision are identified either by VicRoads themselves or through input from local government, local police, the RACV, individuals and organisations.
Factors considered by VicRoads include:
Usually the VLIMITS expert computer system will then be used to assist in determining the appropriate speed limit for the particular length of road.
The recommended limit is then discussed with the local municipality and Police and comment obtained prior to approval being granted by the VicRoads Regional Manager.
In the event that any of the parties dissents or a dissenting view is expressed there is a procedure for resolving the issue. Initially the VicRoads Regional Manager will endeavour to settle the matter and if this is not possible the case is referred to the VicRoads' Director - Regional Services. [5] Occasionally either the RACV or the local community has still been unhappy with the outcome and the issue has been discussed by the Speed Management Policy Committee. Mr J. Sanderson representing the RACV mentioned two locations, one in Beaconsfield Parade (in South Melbourne) and the other in Bairnsdale, where there have been problems because of local perceptions of the use of those roads. [6]
The Committee concluded that the procedures to identify roads where speed limits need to be revised were working satisfactorily.
The responsibility for the on-going evaluation of the impact of the overall speed limit revision was initially unclear. The Royal Automobile Club of Victoria submission recommended that:
The Speed Management Policy Committee should be given the on-going responsibility for the evaluation of the speed management strategy. [7]
VicRoads was asked to comment on this suggestion and on other aspects of the evaluation of the speed revision changes. For example:
VicRoads' reply was that:
Table 5: Schedule of Speed Measurements
Location Before Speed First After Second After Third After
Changes Measure Measure Measure
Urban sites Aug 1993 Nov 1993 Nov 1994 May 1995
(RACV) (RACV) (planned)
Rural sites Nov 1992 May 1993 Nov 1993 May 1994
With regard to the RACV recommendation VicRoads said that:
It would be appropriate for the (Speed Management Advisory Committee) to be involved in the evaluation process but ultimately responsibility to report back to the Minster should rest with VicRoads.[9]
4.4.1 Adequacy of VicRoads monitoring
Both the RACV and Municipal Association of Victoria representatives at the public hearing were critical of the adequacy of the VicRoads monitoring.
Mr J. Sanderson, Assistant General Manager, Royal Automobile Club of Victoria said:
MR SANDERSON - VicRoads should certainly be doing far more monitoring of the situation than it is doing. It is really the state road authority's responsibility to monitor what is happening on the road network. If you were looking at it from a statistically rigorous approach we probably do not have sufficient information and VicRoads should certainly be collecting far more than we are doing.
THE CHAIRMAN - That is precisely the point I was making earlier on. It is quite possible that VicRoads and the RACV are not using the same rules. If you are not using the same rules then you are not proving anything, are you?
MR SANDERSON - In the collection of data we are using the same rules. We use exactly the same procedures, which are well laid down as part of the traffic engineering practices. What I am saying is that we have done four links in each speed zone. Perhaps if you wanted to go to real statistical rigour you may have to do 10 or even 20 to get the proof of change or whatever. So ours is, if you like, a cursory monitoring of what is happening on the network; it is not meant to be the detailed work which should overtake that being done by the local road authority. It should be doing that work as well as ourselves.
THE CHAIRMAN - And you contend that they are not doing that work adequately?
MR SANDERSON - They do not have the same amount of information we do so therefore I would have to say that, yes. [10]
Mr F. White of the Municipal Association of Victoria said:
MR WHITE - The Speed Management Policy Committee was very conscious that monitoring was an important phase of the entire program and the question was raised of at what level monitoring would be done. The committee looked at what monitoring should be done and when the issue was raised at meetings we were assured it was being done. It was only later because we had not had any figures back at that stage that the question was asked, 'How is the monitoring going and what are the figures like?'. The RACV was doing its own monitoring for its own purposes.
THE CHAIRMAN - Are you saying that VicRoads did not do any monitoring for a certain period?
MR WHITE - No data was presented to the committee. Although the accident data was being collected, no monitoring that I am aware of was going on to measure speeds before the change.
THE CHAIRMAN - By that you are referring to the measuring of speed in the zones that were later altered?
MR WHITE - Part of it was also to take measurements in zones in which speeds were not going to be altered to check whether there was any change, any spill-over effect.
THE CHAIRMAN - So far as you know that preliminary work was not done?
MR WHITE - To my knowledge it was not done.
THE CHAIRMAN - What about measurements after the changes were made? Do you know whether those measurements were done?
MR WHITE - I am not certain whether that was done. I have been advised it is being undertaken but I am not certain at this stage whether it has physically been done. [11]
The Committee also questioned the VicRoads representatives at the public hearing about the level of monitoring conducted by VicRoads and concluded that VicRoads appeared not to have adequately conducted comprehensive travel speed monitoring prior to the change of speed limits. [12] Fortunately the RACV of its own initiative collected data for its own purposes which has been passed on to VicRoads and this now forms the pre-change basis for the assessment of the effects of speed changes in the Melbourne metropolitan area.
4.5.1 Introduction
This section covers the procedures for monitoring the effects of changes in vehicle speeds, speeding offences and road accidents, as distinct from the actual effects themselves (which were described in Chapter 3).
4.5.2 Monitoring vehicle speeds
As mentioned above in Paragraph 4.4 the lack of VicRoads vehicle speed data prior to the change in speed limits significantly impacts on the assessment of the effects of changes in speed limits. At the public hearing there was some questioning of the compatibility of the measurement techniques used by the RACV and VicRoads. The evidence was that the techniques themselves were suitably comparable. However one important aspect not able to be assessed by the Committee was the selection of the number and location of road sections used for the before and after comparisons. The Committee is not in a position to judge whether the sites chosen, entirely by the RACV in the case of urban sites, were sufficient or a truly representative sample of the various speed zone changes.
In comparing the information on vehicle speeds included in Appendices F and G it should be noted that the methods used by the RACV for the metropolitan roads and VicRoads for the rural freeways are quite different. The RACV used a radar gun and measured only cars travelling at their 'free speed' (ie. with at least 4 seconds headway). However VicRoads relied on a pneumatic tube measuring device placed across the roadway which automatically measured all vehicles, regardless of whether they were being hampered by slower traffic. Also the VicRoads speed results were less precise, because observations of speed were not individually recorded, but placed in (generally) 5 km/h groupings. This meant that small changes in vehicle speed might not be detected.
4.5.3 Monitoring traffic offences
The Victoria Police submission included a table listing sites where speed cameras detected a high proportion of drivers exceeding the speed limit (plus enforcement threshold). If a site consistently appeared on these monthly lists the appropriateness of the speed limit was raised with VicRoads.
4.5.4 Monitoring accidents
Because no accident analysis has yet been undertaken the adequacy of the monitoring procedures is unknown. Of some concern is the various responses from witnesses on when a statistically adequate accident analysis will be possible. As mentioned in Chapter 3 the Committee considers that the statistical calculations should be done as soon as possible to clearly determine when such analyses can be undertaken. The subsequent analyses should then be done at the earliest possible date.
The implementation of the speed revision program appears to have been generally well conducted and the outcome satisfactory though unconfirmed by detailed accident analysis. The time required for the implementation was longer than originally planned and significant liaison was required with local government, local police and the RACV.
However the monitoring of the outcomes by VicRoads was not well conducted. The Committee finds:
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