There seems to be a consensus here that "many-to-many" (or "anywhere, anytime") DRT doesn't work in rural areas - and probably not in most suburban areas. This variant of DRT seems to be worse than scheduled bus for the ability to nudge people into travelling in the same direction at the same time.
But where is the hard evidence that might cause local authorities to pause and wonder whether they are sure they can buck a well-established trend when they propose yet another many-many DRT scheme?
For all the millions spent on trials and pilots, I can't find any evaluations with the sort of data that would help others learn lessons. There is the odd academic article, but even these shrink from trying to analyse the success of an individual scheme.
So, there seems to be a screaming need for a measure of success that is reasonably meaningful. But that seems really hard.
"Passengers per day" can give some idea - but is open to distortion if the service includes home-to-school runs: - a couple of nearly-full runs could mask low usage for the rest of the day. And in a mixed service area, with 2-mile trips to suburbs and 10-mile trips to distant villages, your not-too-bad numbers might mask the fact that you were doing a really bad job of serving those in the most need. (Both uncertainties applied to the data that I got from Derbyshire CC on their DRT around Ashbourne).
Two other obvious measures - Average passengers on the bus at any time, average bus miles per passenger - can identify services that aren't being used very much if the numbers are low, but not so good if the numbers are higher. They are particularly open to distortion where passengers only reach their destination after being taken "round the houses" - as graphically shown in this example from
Roger French's blog:
![img_7046[1].png img_7046[1].png](https://www.railforums.co.uk/data/attachments/104/104941-d819e34c7b28a7bea9d4975473ef24ac.jpg)
Direct route 2.6 miles; actual mileage 10.5 miles.
Another way of measurement would be to try and supplement data on passenger trips with data on the passenger experience - trying to assess how many of those who would have travelled by scheduled bus are getting to make the trip using DRT - and how many are not.
Some of those not travelling will be captured as failed requests by the better computer systems, and could presumably be identified through appropriate Freedom Of Information requests. But if there is a problem of low availability, many people will quite quickly give up trying, and so won't continue to manifest in the data. Would we expect them to disappear without trace, or would we expect letters to local newspapers (where they still function) or other protest? There doesn't seem much evidence of any negative feedback - why not?
To play Devil's Advocate, is it possible that a substantial proportion of "no-longer" users aren't that bothered? If we are comparing usage over several years (especially if you exclude a year or two for Covid), then there will be a fair number who, sadly, have died. But we would expect them to have been replaced by others whose health or finances have changed during that period to mean that they have started to need public transport. Perhaps they aren't vociferous because they don't know what level of service they ought to expect?
Others might have been marginal users - I had an elderly neighbour who used to ride 5 miles into the local town most days and return with just one or two items: it "helped pass the time".
Where we see timetabled services with significant (but non-commercial) levels of usage that are replaced by DRT that is moving substantially fewer people, is there an invisible problem of non-served needs? Or isn't there that much of a problem?