It's a bit of both, and very important to point out the distinction
A mix of busways, plus developing the park and ride sites as part of this. Possibly also developing the "county" bus routes to run more frequently, and also operate evenings and Sundays too (most don't)
Cambridge's basic "problem" is that it's catchment area is scattered around a wide range of disparate villages (where housing is much cheaper), which individually can't (in general) sustain commercial bus services, but combined lead to a significant traffic flow into the city.
That makes sense. Being a relatively flat part of the country, just providing good biking infrastructure to those park and rides, alongside parking would make a lot of sense.
I frequently use the new e-scooters for last mile trips up here in Salford! They are also great to use on dedicated cycle routes.
Good that this nonsense has been cancelled. However I think the very basic idea of a tunnel for buses makes much more sense for a city of Cambridge's size. If it had just been designed as a route for single decker guided buses using the same system as the existing busway then all the technology risk/expense would be avoided. The city and surroundings would all benefit immediately, rather than just one route which would be the case with trams, as I can't imagine the Treasury coughing up for a network in one go.
I like this idea, it would probably be similar to the Adelaide guided busway. Considering how much busway infrastructure already exists in Cambridge, it makes sense to expand on it. I'm sure with the use of articulated buses (with multiple doors) and smart fare payment, you could run a pretty efficient system.
For longer routes that need higher capacity, just extending some of the local rail network as a seperate project would probably make sense.
Diesel engines running in a tunnel? Sounds atrocious for air quality for the passengers.
I mean car tunnels exist, you just need a LOT of ventilation. It would almost certainly be electric buses anyway.
Would an exclusive bus corridor like in some French and Spanish towns deliver most of the benefit without the expense and engineering challenge of tunnelling through what is probably wet fen ground? A tunnel would require routes reorganising to one corridor to use it anyway.
I think with the tight, narrow streets, a tunnel could provide a lot of journey time benefits. It would probably be an underground BRT style thing.
Full battery buses. If TfL can do it, any city can.
I don't think it's a bad idea, but if there's an opportunity for in-motion charging, that might be worth looking at. Ultimately depends what the economics of it turns out to be. I think OLE provision on key corridors could be economic, but most manufacturers don't really have a modern mass-market solution for it. Old trolley designs aren't really suitable, but something that tracks two wires electronically would be quite resillient and likely require much less special training.
However, with an integrated system, bus charging could be quite easily worked into the bus stops. I can imagine it working quite well out at the P&R's, giving the buses say a 30 minute turnaround time, charging from an overhead connection whilst parked in the bays.