I went on a training course today, and chose to take the train to the venue instead of driving. I arrived back at Cambridge station at 1740, and went in search of a bus. As I came out through the station entrance, I saw one of the new guided buses on the roundabout – it was snarling up the traffic as it was waiting for temporary traffic lights on the new access road that leads to the guideway. In my transport-fanboydom, I set off at speed down the footpath to the new bus stops for the guided busway, only to miss the said bus by about a minute. Bother. I looked at the timetable: this is peak hour operation, but the frequency on the southern part of the busway (which goes to Addenbrooke’s Hospital and Trumpington) is only one bus every 20 minutes. I walked back to the main bus stops and checked the timetable there. Normal, non-guided buses run to Addenbrookes every 5 minutes, and to Trumpington every 10 minutes. This begs the question: what is the southern section of the guided busway actually for?
Let’s have a look at the timetables. Only one of the four busway routes uses the southern section at all: route A, operated by Stagecoach. This operates one bus every 20 minutes right through the day, stopping abruptly in the early evening: the last buses are at 1830 from Cambridge and 1839 from Trumpington. A note hidden at the bottom of the timetable shows that there are an extra hour’s worth of bus services between Trumpington and Addenbrooke’s after the main service finishes.
The journey times on route A are as follows:
Trumpington – Addenbrookes: 6 mins
Trumpington – Rail station: 13 mins
Trumpington – City centre: 22 mins
Addenbrooke’s – Rail station: 7 mins
Addenbrooke’s – City centre: 16 mins.
Okay, so how does this compare with the conventional bus services? The guided buses have a dedicated route from the railway station to Addenbrookes and Trumpington, but going into the city they are on the road.
Let’s take the Trumpington – City case first. On this route, the guided buses compete directly with the Park & Ride shuttle bus, which makes no intermediate stops between the P&R site and the city. The P&R buses run every ten minutes (twice as often as the Route A buses) and take 16 minutes for the journey. So they are 5 minutes faster than the guided buses, despite being on the road the whole way! As they run twice as frequently, the average journey time for a passenger arriving at the P&R site is 21 minutes (5 mins avg wait + 16 mins journey) for the P&R buses and 32 minutes (10 mins avg wait + 22 mins journey) for the guided bus.
How about Addenbrookes – Railway station? This bit is on the guideway, and so should be faster. And so it is – 7 minutes for the guided bus, as against 10 minutes for the conventional service. However, as the guided bus is only every 20 minutes, whereas the Citi 1, Citi 7 and Citi 8 services combine to provide a bus every five minutes. If you walk out of Addenbrookes at some randomly-determined time and go to look for a bus, you would on average wait 2.5 minutes for a conventional bus, followed by a 10 minute journey time – i.e. 12.5 minutes total journey. However, your wait time for a guided bus will be an average of 10 minutes, followed by a journey time of 7 minutes, making 17 minutes average total journey time. So the guided bus is not much use for going to the station from Addenbrooke’s. The same argument applies to taking the bus to the city from Addenbrooke’s.
Okay, so what about Trumpington – Addenbrooke’s? Maybe the idea of the southern section is to act as a P&R service for the hospital? Well, firstly the every-20-minutes frequency is not exactly encouraging. Secondly, parking at Addenbrooke’s for hospital visitors is not astronomical: £3.50 for 2 hours costs the same as a Dayrider ticket on the guided bus. Thirdly, Addenbrooke’s has a nice new access road that connects it to Trumpington P&R site and the M11, so if a hospital P&R service was required, there was no real need to build a fancy new busway – the buses could just as easily use the new access road.
So, to summarise: the guided buses only offer faster journey times on certain parts of their route (and even then we’re only saving three minutes) but their low frequency means that most people will be better served by the conventional bus service. Providing a P&R service between Trumpington and Addenbrooke’s could have been easily done without the guideway. So what exactly is the southern section for? I still don’t know…