Given that driving and parking within Cambridge city centre is worse than London, it makes perfect sense to park your vehicle here and pick up a plus bus ticket for the day.
There's loads of parking space and as far as I could see the frequency of buses to downtown Cambridge is quite high.
You can pay for parking and pick up bus tickets at the automated ticket machines on location.
However if you are taking the train into the city and have a network rail card, it is best to buy your discounted plus bus ticket as an add on to your train ticket read more