Have you ever used the WHT? It's practically EMPTY all day, even in peak hours .... so you don't need to encourage more people to cross, you just need to MOVE them from the CHT to the WHT and both will be improved. That's the sensible thing to do. I don't think there are many CARS going through - when I come thru in my bus, it's mainly buses and taxis at peak hours. Not that many cars. I agree with your point re goods vehicles though - they really should be incentivised to travel only in offpeak hours and time based pricing is good for that, although likely to result in traffic jams/arguments for about 10 mins either side of the slots!