EVALUATION OF THE "KEEP LEFT UNLESS OVERTAKING" REGULATION

On 1 March 1988, a regulation was passed which made the previously advisory 'Keep Left Unless Overtaking' (KLUO) zones (indicated by signs) regulatory. These signs are placed only on high standard sections of urban and rural freeways and divided arterial roads in rural and "outer" urban areas where there is a limited need to be in the right hand lane for right turns, parking and standing in the left lane is also not allowed, and where moderate traffic volumes prevail. Signs are also located where climbing and overtaking lanes are provided. This study examined whether there were any effects of the regulation and accompanying publicity and enforcement on driving behaviour at freeway and divided arterial road locations throughout Victoria. There was a significant increase in the proportion of cars travelling in the left lane after the regulation was introduced. Specifically, there was a 3.6 per cent increase at KLUO zones and a 5.0 per cent increase at similar locations where KLUO zones do not apply, for cars overall. For free speeding cars there was an increase of 7.4 per cent in left lane usage where advisory KLUO zones became regulatory and a 12.0 per cent increase at similar locations where KLUO zones do not apply. A marginal increase was detected for trucks, the majority of which already travel in the left lane (almost 90 per cent). Two factors were found to be associated with left lane usage. The increases in left lane usage is characteristic of motorists who drive at/or below the speed limit. Additionally, the traffic volume on a route is directly related to the degree of left lane usage (A).

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• Corporate Authors:

  ROAD SAFETY DIVISION

  290 BURWOOD ROAD
  Hawthorn, Victoria,   Australia 
• Authors:
  • Zutshi, I
  • Cavallo, A
• Publication Date: 1989-9

Language

• English

Media Info

• Pagination: 58 p.
• Serial:
  • Issue Number: GR89

Subject/Index Terms

• TRT Terms: Arterial highways; Behavior; Climbing lanes; Data collection; Driving; Freeways; Law enforcement; Passing; Publicity; Rural areas; Speed; Speed limits; Traffic flow; Traffic lanes; Traffic regulations; Traffic signs; Traffic surveys; Trucks; Urban areas; Vehicles
• Uncontrolled Terms: Zone
• Geographic Terms: Australia
• ITRD Terms: 8006: Australia; 9001: Behaviour; 2808: Climbing lane; 8623: Data acquisition; 1855: Driving (veh); 1534: Enforcement (law); 1236: Lorry; 2748: Main road; 2752: Motorway; 1822: Overtaking; 8573: Publicity; 378: Region; 328: Rural area; 5408: Speed; 624: Speed limit; 671: Traffic flow; 2827: Traffic lane; 1544: Traffic regulations; 553: Traffic sign; 676: Traffic survey; 313: Urban area; 1255: Vehicle
• Subject Areas: Law; Motor Carriers; Security and Emergencies; Vehicles and Equipment;

Filing Info

• Accession Number: 00604942
• Record Type: Publication
• Source Agency: Transport and Road Research Laboratory (TRRL)
• ISBN: 0-7241-7342-0
• Report/Paper Numbers: -2
• Files: ITRD, TRIS, ATRI
• Created Date: Feb 28 1991 12:00AM