Hull’s Spurious Road Safety Claims       

Representatives from the city of Kingston-upon-Hull repeated their spurious claims about the success of their traffic calming schemes at the recent GLA Transport Committee Inquiry into speed humps.  Their claims for major reductions in road accident have received widespread publicity in the last few months, but the data is in fact seriously flawed.  

Hull has installed road humps, 20 mph zones and other traffic calming devices in over 500 streets in the last few years. That’s about 25% of their total road network, so they are probably one of the most heavily treated areas in the country. They claim the following reductions in accident data since 1994: 

The above is an extract from their report to the Greater London Assembly speed hump Inquiry. Unfortunately there are a number of mistakes in their report. The reality is that they have not obtained any better reduction than the UK as a whole, so clearly the investment has been mainly wasted. The mistakes are as follows: 

Great Britain Casualty Reduction is Wrong

The figure on which they based their -1% reduction for overall UK casualties is simply wrong, with the result that it should be -4%. That reduces the overall “improvement” to 10%. 

No Adjustment for Population Changes 

They have not taken into account that the population of Hull is one of the few in the UK which has fallen substantially in the last few years. With fewer people on the streets, there are fewer accidents!  In reality the population fell by 8% between 1994 and 1998 so taking that into account the reduction is only 2%. Also the overall UK population increased by 2% in the same period, so the net effect of these changes is to remove any remaining difference.  In summary there is no overall casualty benefit from the measures taken in Hull, when compared against the UK as a whole.

A comment: Of course it could be that people are leaving Hull because they are fed up with all the speed humps, but that may be too far fetched a conclusion.  

Selective Data Only Shown 

It may still look good that they have reduced pedestrian injuries by 44%, but unfortunately this is a very selective figure which is also distorted by the fact that the young and mobile are the first people to leave a declining city.  What they fail to mention is that car occupant injuries actually went up by 28% in Hull from 1994-1998, while they fell in the same period in the UK as a whole. So much for the success of speed humps in Hull!  The trends in car accidents in Hull are shown in the following graph (reproduced from the Hull City web site - the top line shows the overall car occupant trend): 

In reality Hull demonstrates an extreme example of what was revealed in one of our recent newsletters - namely that pedestrian and cycling accidents have been falling as people have moved into cars. Incidentally according to a BBC television report, Hull is also one of the worst cities in the UK for health problems related to obesity. No doubt this is related to the above changes. 

The major concern about the claims by Hull is that not only have they wasted an enormous amount of money which would have been more effectively spent on other road safety measures, but that they may encourage others to do the same. Note that BBRAG can supply the detailed evidence to support the above arguments if you need it.   

One thing that is useful about the Hull data however, is that it demonstrably shows that wide area traffic calming schemes have no beneficial impact whatsoever.

R.W.Lawson, 2004

Back to London Assembly Inquiry Page