The average speed reduction of around 1mph is in keeping with the findings of the TRL research for sign-only schemes. Noise and air quality is relatively unchanged, as the traffic volumes are not significantly changed. To evaluate project outcomes in terms of the resident communities' attitudes and to assess the scheme impact on other parties, e.g. Police. 8.6 The consultations with local representatives indicate that in areas adjacent to the trial sites there is a desire to have similar schemes. The analysis in Chapter 3 shows that there is a relationship between the length of the road network and the potential speed reduction.
Longer lengths are more likely to show speed reduction.
There also seems to be a relationship between the number of houses and the potential speed reduction with more houses likely to correspond with speed reduction To use research evidence to compare the value for money of these low cost measures with more traditional engineered schemes. The accident information provided shows a reduction in the annual number of accidents from 31.3 per annum to 18.2 per annum when factored to equivalent time period Table 4-2. The total cost of all 66 schemes is 317,000. The Research Reports reviewed in Chapter 6 do not specifically address value for money in the engineered schemes, however, The value for money of sign-only schemes seems apparent as illustrated in Chapter 7. The majority of the trial sites have not been successful in obtaining an average speed of 20mph.