1. Insert the title of your presentation here Presented by Name Here Job Title - Date Reducing spread rates to save salt Presented by Richard Jordan Principal Researcher – 24 March 2010

3. Salt distribution and salt loss trials Page 

4. Poor distribution profile and high wastage Page 

5. Dry, pre-wetted and treated salt Page 

6. Reasonable distribution with little wastage Page 

7. What can be achieved with correct settings for de-icer Page 

8. Dry salt Page 

11. Effect of salt distribution and salt loss on spread rate Page  Target salt at forecast conditions (g/m 2 ) Minimum initial dosage relative to nominal spread rate Salt remaining after trafficking Required nominal spread rate (g/m 2 ) Salt saving 5.0 80% 40% 15.6 5.0 85% 45% 13.1 17% 5.0 90% 50% 11.1 29%

12. Surface state definitions (from Raukola et al, 1993) Page  Definition Water (g/m 2 ) Water film thickness (mm) Description Little moist 5 – 20 0.005 – 0.02 Detectably dark road surface Moist 20 – 50 0.02 – 0.05 Clearly dark road surface Wet 50 – 200 0.05 – 0.20 Spray phenomenon starts Very wet 200 – 400 0.20 – 0.40 Small drops of water in the air Flowing >400 >0.40 Flow according to gradient, splash

13. Proposed spread rates (1) Page  Weather and road conditions Old dry salting spread rate (g/m 2 ) New dry salting spread rate (g/m 2 ) New pre-wetted salting Spread rate (g/m 2 ) Salt content (g/m 2 ) Frost or forecast frost RST at or above -2˚C 10 8 8 6.2

14. Proposed spread rates (2) Page  Weather and road conditions Old dry salting spread rate (g/m 2 ) New dry salting spread rate (g/m 2 ) New pre-wetted salting Spread rate (g/m 2 ) Salt content (g/m 2 ) Frost or forecast frost RST below - 2 o C and above - 5 o C and dry or damp road conditions (50% more if damp and lightly trafficked) 20 10 9 6.9 Frost or forecast frost RST below - 2 o C and above - 5 o C and wet road conditions (50% more if lightly trafficked) 16 15 11.5

17. Page  Thank you Reducing spread rates to save salt Snow Summit 2010 Presented by Richard Jordan Principal Researcher – 24 March 2010 Tel: 01344 770828 Email: rjordan@trl.co.uk