Sunday, June 14, 2020

Two forms of logic: PTV website vs railway safeworking

It's only just occurred to me that various parts of the public transport network operate to different forms of logic. For example railway signalling systems are designed to fail safe. That is unless they're sure that everything is fine the system will assume a fault and stop everything until it's checked out and cleared. 

Whereas in the world of passenger information a less rigorous 'no news is good news' logic is used. Thus the PTV website might say that a bus route is operating properly ('good service') even though it's a new route that doesn't start until next month. It says this because no bad news has been received. And there's apparently no checking of data output, despite it in this case being nonsensical. Here's a Twitter exchange describing these different mindsets. 



Here's a thought experiment. What would happen if you put engineers in charge of websites and website dudes in charge of train signalling? The former may well be correct but (possibly) incomprehensible while the latter might end up a trainwreck! 

You might enjoy these well-regarded books on transport topics

Better Buses, Better Cities: How to Plan, Run, and Win the Fight for Effective Transit Steven Higashide 

The Public City: Essays in honour of Paul Mees Gleeson & Beza

A Political Economy of Access: Infrastructure, Networks, Cities, Institutions (Access Quintet Book 4) David Levinson

Human Transit: How Clearer Thinking about Public Transit Can Enrich Our Communities and Our Lives Jarrett Walker

Transport for Suburbia: Beyond the Automobile Age Paul Mees

(Sales links: I get a small commission if you buy via the above - no extra cost to you)

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