Exercise 1A, Appendix W of the Study Pack

[merlin89]

SBD - Service Braking Distance as from the signal spacing chart GK/RT0034 so this would be 1258 m at 80 mph on level gradient

BD - Safe Minimum Braking Distance (as you can see I have also used B in places)

As the question asked for maximum permitted spacing for 3 aspect I took this to be Service Braking Distance + 33% = 1258 m+ 33% = 1673 m and not the Safe Minimum Barking Distance which was 900m ..not sure about this in regards to the question..

Good hint on the sighting distance calc will definately use that in future I also think Ill start to sketch out the aspects with dimensions to make these stick.

Thanks for your time Reuben