Sample data
 
Hypothetical Data
 
The following is hypothetical data for a particular car:
 
Date Time Street Town Postcode Road number
Friday, 01 July 2005 08:12 127 High Street Beckenham BR3 1AG A234
Friday, 01 July 2005 08:20 142 High Street Penge SE20 7EU A234
Friday, 01 July 2005 08:29 97 Lordship Lane London SE22 8HU A2216
Friday, 01 July 2005 08:34 37 Denmark Hill London SE5 8RS A215
Friday, 01 July 2005 08:41 10 Walworth Road London SE1 6SP A215
Friday, 01 July 2005 09:15 74 Blackfriars Road London SE1 8HA A201
Friday, 01 July 2005 09:16 33 Belmont Road Liverpool L6 5BG A5089
Friday, 01 July 2005 09:25 167 Fleet Street London EC4A 2JB A4
Friday, 01 July 2005 09:29 105 The Strand London WC2R 0AA A4
Friday, 01 July 2005 09:32 5 Trafalgar Square London SW1Y 5BJ A4
Friday, 01 July 2005 18:32 5 Trafalgar Square London SW1Y 5BJ A4
Friday, 01 July 2005 18:36 105 The Strand London WC2R 0AA A4
Friday, 01 July 2005 18:45 167 Fleet Street London EC4A 2JB A4
Friday, 01 July 2005 18:55 74 Blackfriars Road London SE1 8HA A201
Friday, 01 July 2005 19:14 10 Walworth Road London SE1 6SP A215
Friday, 01 July 2005 19:24 37 Denmark Hill London SE5 8RS A215
Friday, 01 July 2005 19:29 97 Lordship Lane London SE22 8HU A2216
Friday, 01 July 2005 19:35 142 High Street Penge SE20 7EU A234
Friday, 01 July 2005 19:49 127 High Street Beckenham BR3 1AG A234
 
Above is a snapshot of the data-points for a certain car for the the 1st July 2005. A person who is knowledgeable of London and its suburbs would be able to state the following with absolute certainty:
  1. The data point for Liverpool (at 09:16) is incorrect and should be discarded.
  2. The car started travelling into London shortly before 08:12
  3. The car was either held up or parked for a short while at around 08:45
  4. The car commenced a return journey just before 18:32 and arrived at its destination shortly after 19:49
Clearly, a similar interpretation of the data can be made by a computer program and this driver can be billed for 2 trips during peak periods.
 
The proportion of the bill for this driver can be divided between each of the providers of correct data. On the other hand, the provider of the incorrect (Liverpool) data can be penalized for the error.
 
Clearly, the more data is collected, the greater the accuracy of the resulting road-pricing calculation. However, Pareto's Principle (the 80-20 Rule) applies in traffic like in so many other areas - 20% of cars create 80% of the congestion. It is believed that the whole of the UK can be adequately monitored for with only 10,000 cameras - one per 3,100 vehicles.