As a business owner and commercial rate payer I would say that the 20mph zone in Marchmont has been a qualified success.
We opened before this was set up and have seen more families walking and cycling to school with much fewer drivers ignoring the limit. A few still do of course (hence the use of qualified) but generally people understand that this is an area where people like to walk (or cycle) between local businesses. There are no marked crossings on this street and the advent of 20mph zones means that a minor adjustment of speed can allow the young and old to get across safely. From a driving point of view the absence of light controlled crossings will actually make driving less frustrating. Also will save money.
We run a bike shop so readers may think that we are immune to any laws that pertain to cars. In fact the 20mph zone also helps with parking as when a street is marked at 30mph it means that finding that elusive parking space can annoy fellow car users. When the local retail environment is slowed slightly people have time to see spaces and work with each other.
You wouldn't expect to drive round a shopping centre car park at 30mph. What's good enough for the large supermarkets is good enough for the business and council tax payers who actually live and work on these streets.
The city streets are not just there for people 'passing through' and a more pleasant outdoor environment results in more time spent at local shops, cafes and pubs.
Laid Back Bikes