Appendix 5 20Mph Speed Limits Report

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Appendix 5 – Example assessment flowchart 
Existing 30mph
where agreement has
been reached to trial
20mph speed limit 
Carry out a pre-
implementation
traffic volume &
speed survey 
Introduce 20mph
trial speed limit
After agreed “bedding
in” period, carry out
post implementation
traffic volume & speed
survey
Using the speed limit
+10% +2mph method,
if the mean speeds are
less than 24 mph, the
20mph speed limit can
be made permanent.
If the mean speeds are
greater than 24mph
but further funding is
provided by Scottish
Government to
introduce physical
traffic management
measures which would
achieve speeds less
than 24mph, the
change can be made
permanent.
If the mean speeds are
greater than 24mph
and no further funding
is provided by Scottish
Government, subject
to agreement with the
relevant Area
Committee, the speed
limit should revert to
existing 30mph limit.