mudguard:
I actually think Auckland has too many on/off ramps and many are too short. Yes in theory you should be merging at 100kmh, but on some you do need to accelerate briskly to get there. Plus there are few on ramps that you have to compete with people getting ready for the off ramp.
My wimpy i20 is regularly held back by fellow motorists who refuse to accelerate down the on ramps. If I can do it with 1,396cc, they should be able to too. Many have much more power at their disposal than I do.
EDIT: I can hit 100k on most on ramps just fine... manual though.