Placing transport infrastructure underground will dramatically improve our quality of life above-ground. Congestion and noise would be reduced, and inner City air quality would be improved. The number of buses operating in the City centre would be reduced.
Moreover, the Cambridge Coach Station could be relocated from the City centre to either the Girton Interchange or Hauxton / Trumpington Park & Ride site in the south. With fast Light Rail access from there, coach access into the City centre would almost become unnecessary. Tourists travelling by coach, and locals making longer-distance journeys, could use the rapid Light Rail link to access the coach station at the periphery of the City. This could offer significant advantages to coach operators as well, since they would no longer suffer the delays often experienced when accessing the city centre, particularly at peak times. This would enable more punctual timetabling and improve the profitability of coach companies.
Fewer buses and coaches would enhance the space within the City centre: with fewer large vehicles blocking narrow lanes, the urban space will feel more safe, open and pleasant. It could open up more opportunities, for example, to enhance spaces with pedestrian areas, street cafes, and so forth. The space for pedestrians and cyclists would be enhanced, and safer. Long-term, this would make the inner city a much more attractive place to visit, shop, and just hang out. That would be good for visitors and locals, and for inner city businesses.