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    <copyright>Copyright © 2026. National Academy of Sciences. All rights reserved.</copyright>
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    <managingEditor>tris-trb@nas.edu (Bill McLeod)</managingEditor>
    <webMaster>tris-trb@nas.edu (Bill McLeod)</webMaster>
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      <title>Global Approaches to Setting Speed Limits</title>
      <link>https://trid.trb.org/View/1249468</link>
      <description><![CDATA[Static maximum speed limits are set to inform motorists of appropriate driving speeds under favourable conditions, and are almost always enacted with an overarching goal of increasing safety while retaining reasonable mobility. The first speed limits actually predate the automobile, and as such they have a long and varied history in protecting the traveling public. Today, the speed limit is by far the most popular tool used by engineers and traffic engineering professionals to manage travel speeds. Besides being a popular Canadian road safety tool, speed limits are almost universally employed by all motorized countries. Despite the long and wide-spread use of speed limits as a road safety tool, there are numerous speed limit setting methodologies, and there is no consensus in the traffic engineering community on a single speed limit setting methodology. While there are literally countless guidelines/methods for setting speed limits, these methods can be roughly categorized into four general approaches. The purpose of this paper is to outline the four general approaches to setting speed limits that are available to the transportation engineering community, and to discuss the strengths and weaknesses of each. The four approaches to setting speed limits are the engineering approach(including the traditional use of the 85th percentile speed, and the road risk methodology), the expert system approach (including VLIMITS, USLIMITS), optimization(using speed limits to minimize the total societal costs), and the safe system approach (linking road types and crash types to travel speeds). (A) For the covering abstract of this conference see ITRD record number 201211RT334E.]]></description>
      <pubDate>Wed, 01 May 2013 13:20:09 GMT</pubDate>
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      <title>Speed limits: RACV's perspective: a submission to the Parliamentary Social Development Committee</title>
      <link>https://trid.trb.org/View/1199021</link>
      <description><![CDATA[The RACV has undertaken speed surveys at some 80 locations to provide information for this submission which show a continuing disregard for current limits.  However, many of the limits are inappropriate.  The RACV has checked the appropriateness of speed limits at many of these locations using the Expert Systems Analysis (VLIMITS) developed as a result of the previous Speed Management Strategy for Victoria.  These analyses illustrate a need to complete a major review of speed limits.  The brief review of speed and crashes contained in this submission demonstrates that crash involvement is related to diversity of speeds rather than speed per se. It also demonstrates that speed may only be a factor in some 5 per cent to 10 per cent of urban crashes and in a maximum of 25 per cent of rural crashes. Greater road safety benefits may be achieved by improved road design, blackspot countermeasures, improved vehicle occupant protection and enforcement of behaviour associated with increased risk of involvement in crashes rather than concentrating on reducing speed.  The RACV is concerned about the emphasis placed on speed enforcement, particularly now that the Victoria Police are to be provided with 60 speed cameras.  The RACV is also concerned that the police are being seen as revenue raisers on behalf of the Government, rather than enforcing legislation related to road safety. The RACV accepts the need to prosecute motorists who drive at 'excessive' speeds but finds the concentration on minor infringements inequitable and unnecessary.  The RACV supports the policy developed by the police for the use of speed cameras.  However, it would appear that the policy is not being used as an operational standard.  The speed limits recommended by the RACV would be: 1) on local streets, a general speed limit of 50 km/h with reduced speed limits of 40 km/h in areas of high pedestrian activity and 20 km/h in shared zones; 2) on urban arterial roads, a limit of 60 km/h on undivided roads, 80 km/h on divided roads and 100 km/h on freeways.  There may be an opportunity to introduce a speed zone of 110 km/h on some suburban freeways; 3) on rural arterial roads, a limit of 80 km/h on access roads, 100 km/h on highways and 110 km/h on freeways.]]></description>
      <pubDate>Fri, 24 Aug 2012 16:26:45 GMT</pubDate>
      <guid>https://trid.trb.org/View/1199021</guid>
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      <title>Experience with an Australian expert system for speed zoning</title>
      <link>https://trid.trb.org/View/1174401</link>
      <description><![CDATA[The paper describes how an expert system shell was used to create a knowledge-based system for determining speed zones.  Having been in operational use for two years, its performance was reviewed.  Due to organisational mergers there were problems with procedures and documentation. This has been largely overcome by the use of a new hypertext facility to include much of the documentation in the advisor.  There was also a problem of "ownership" of the system.  To generate greater user acceptance, the advisor and new documentation will contain reference only to the users' organisation, not the developers, and be prepared in the corporate format. Where there had previously been no formal policy for some aspects of speed zoning the need to formulate expertise in these areas has proved to be a catalyst for policy development.  A parliamentary committee, charged with reviewing speed limits, endorsed the use of VLIMITS as the best available method of setting speed limits and overcoming inappropriate speed zoning. Other Australian states have shown an interest in VLIMITS to the extent that Federal Government support has been obtained to work towards a nation-wide advisor, based on best Australian practice.]]></description>
      <pubDate>Thu, 23 Aug 2012 23:34:18 GMT</pubDate>
      <guid>https://trid.trb.org/View/1174401</guid>
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      <title>VLIMITS: AN EXPERT SYSTEM SPEED ZONE ADVISOR: THE FIRST THREE YEARS.</title>
      <link>https://trid.trb.org/View/516480</link>
      <description><![CDATA[No abstract provided.]]></description>
      <pubDate>Wed, 14 Jul 1993 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/516480</guid>
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      <title>CONTINUING DEVELOPMENT OF AN EXPERT SYSTEM SPEED ZONE ADVISOR</title>
      <link>https://trid.trb.org/View/377186</link>
      <description><![CDATA[This paper starts by briefly outlining the initial development of VLIMITS: an expert system based speed zone advisor for Vic Roads in 1987 and then describes in some detail a review of the first three years of operation of VLIMITS within Victoria.  As a result of the review, (carried out in 1991), a revision of VLIMITS is currently underway.  Factors such as the 85th percentile speed and accident rates will now be included in the decision making process, and the program has been expanded to cater for the new Victorian speed limits of 70 and 80 km/h, which replace the 75 km/h zone.  The final section of the paper deals with the current development of expert system based speed zone advisors for New South Wales (NLIMITS) and Queensland (QLIMITS).  Each one, although based on a similar structure to VLIMITS, uses the procedures, rules and guidelines from the relevant State.  It is anticipated that the development of these three systems will assist in the establishment of an Australian wide system of rational speed zoning.  (A) For the covering entry of this conference, see IRRD abstract no. 843369.]]></description>
      <pubDate>Thu, 01 Jul 1993 00:00:00 GMT</pubDate>
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      <title>VLIMITS: AN EXPERT SYSTEM FOR SPEED ZONE DETERMINATION IN VICTORIA</title>
      <link>https://trid.trb.org/View/301112</link>
      <description><![CDATA[As part of any program of speed management and enforcement, it is important to ensure that speed zoning is rational and consistent.  Those responsible for zoning decisions are often faced with competing pressures and demands from particular interest groups.  At the same time there is a lack of clear guidelines to the public and local authorities on what is an appropriate zone for particular conditions. This report describes the development of a computer 'advisor' program which can indicate the probable zoning decision a group of experts would make in a given situation. The advisor is based on an 'expert system', backed up by extensive data collection and investigation of the zoning decision process.  Field measurements were taken of road cross section, abutting development and traffic speeds at 64 sites covering a wide range of road types and environments. Upstream and downstream road features were also noted.  A number of panel discussions were held with the road traffic authority and the victorian speed limits committee.  These used slides of existing zones, current rezoning applications, and discussion of the zoning decision process to determine the factors which should be used to discriminate in particular cases.  The resulting 'advisor' program is able to reproduce the experts' decisions in the majority of cases, and can indicate cases where the decision is marginal.  The advisor is highly user friendly, requiring no computer knowledge and providing a menu of response alternatives for most questions.  Field data sheets are also provided to assist the user in site inspections.  The research highlighted the importance of abutting development in speed zoning decisions, and found a number of anomalies in existing speed zones (a).  The isbn of the microfiche version is 0-86910-356-3.]]></description>
      <pubDate>Sat, 30 Sep 1989 00:00:00 GMT</pubDate>
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