The LTNs data definitely needs a bit of work IMO. In my neck of Fairmilehead there are four streets marked as LTNs which are open to two-way traffic at both ends - there's no modal filters, no traffic calming, nothing to make it not possible to rat-run through them (which is the definition stated on the map page). I would agree that, because there are parallel streets nearby which are more convenient to use as rat-runs, they don't get used as such particularly heavily, but it's still possible. And surely the point is that, if you close off the more obvious rat-runs, drivers will end up finding their way on to the only marginally less convenient ones.
The LTNs data doesn't seem to be have any way to identify streets that can be used as rat-runs only in one direction. For example, I'd argue that Midmar Drive/Hermitage Drive/Braid Road is currently still a rat-run, albeit only southbound. There are also streets which can only be used for rat-running at certain times (Biggar Road to Oxgangs Road via Swanston Avenue being an example - though I've never seen the morning peak restriction there actually enforced).
I wonder whether there would be a case for including 20mph zones in the mapping? Though their value as a rat-runner deterrent probably depends in part on the length of the restriction. It doesn't seem to dissuade a lot of rat-runners from taking the relatively short 20mph diversion which includes our street, rather than facing the ignominy of having to wait at the traffic-light controlled junction at Fairmilehead.
Despite these quibbles, it looks like a good start.
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