There is plenty of traffic returning from the Happy Valley Road, viz:
Cars unable to park
Cars that have parked and now moving
Cars who went down the road without knowing where they were going
Cars from the Ski Slope
Cars from the Cable cars
Cars from the cafe
Cars from Happy Valley gardens
And, the cars who did not want to pay the toll.
How about telling us how many of each group you have counted?
In the period prior to my retirement I worked for CCBC and was, in fact, responsible for the efficient operation of Marine Drive, and the Tolls. I had plenty of data on all aspects of its operation, especially the problems caused by those arriving at the toll and then wishing to return to town. However the main problem at peak periods was found to be in the area of the HV Car Park where congestion occurred because of the restricted space for manoevering, and the general melee of drivers vying for a parking space. Nuff said.
I return again to my main point - the town was never built to accommodate the volume of traffic we get. As a comparison have a look at other resort towns such as Bournemouth.
Finally, if you have a good idea, the Council will listen. Just get it properly documented and submitted. And, most important, that the project is viable!