This paper examines the benefits of a new type of 'intelligent' road traffic sign, which specifically targets drivers who are at risk or who endanger other road users. It presents strong evidence that, after they meet these signs regularly, drivers become sufficiently aware to become conditioned in advance to avoid activating them. In 1992, a trial was begun on a trunk road in the English county of Norfolk, using an interactive sign displaying a coloured 30,ph speed limit roundel. Its trigger speed was set at the median traffic speed (38mph) and the sign was exposed for 4sec each time it was triggered. The effect was quite dramatic, with mean speed falling from 38mph to 32mph. 85 percentile speed from 43mph to 35,ph, and proportion driving over 35mph fro 67% to 15%. This result was maintained for over three years, until the road was 'detrunked' and the sign was removed. Six similar additional signs were then installed in Norfolk villages in 1995; the villagers' response was very favourable, and local authorities considered them very effective. Norfolk County Council then installed two extra signs, one at a small village and one at a suburban location. The paper details the successful village and one at a suburban location. The paper details the successful trials of these signs and of a simple 'intelligent' bend warning sign; at the latter site, speeds were reduced, and no more accidents occurred. For the covering abstract see IRRD E100674.


  • English

Media Info

  • Pagination: 10 p.

Subject/Index Terms

Filing Info

  • Accession Number: 00764372
  • Record Type: Publication
  • Source Agency: Transport Research Laboratory
  • Files: ITRD
  • Created Date: May 28 1999 12:00AM