Krunchie's Cab: How Krunchie's Cab beat Buses

You normally wait for a bus. In Krunchie's Cab System, a Cab is normally waiting for you.
Only one of multiple buses is yours. You wait at your bus-stop while several other buses pass, before yours comes along. In Krunchie's Cab, you take the first vehicle that comes along, since every single capsule can take you to your destination.
You might need 2 or more buses to get to your destination, but only one capsule.
The bus will rarely take you door-to-door; the capsule always will.
Buses are more expensive: they use more fuel and require more personnel and maintenance.
One Tube route can handle a lot more passengers than a similar Bus route. Replace a bus route by Krunchie's Cab and increase the capacity from 5,000 to 500,000 passengers per day.
A Tube takes up less road space (and can be raised off the ground to use zero road space, if required).
Buses cause and are affected by traffic congestion: Tubes are congestion-free.
Buses are subject to road accidents. Tubes are accident-free.
Krunchie's Cab is not affected by strikes.