> Why don't they asphalt curb to curb for a mile and then come back and do the ramps one at a time?
As someone who did a stint in this kind of construction: not possible, you'd still need to re-pave about 30-50cm worth of road, because curbstones are (usually) suspended in a bunch of concrete to avoid them getting dislocated by cars hitting or driving over them. The result will be a faultline from which you will get potholes in freeze cycles.
The proper way is to do everything at once, leaving one slab of contiguous asphalt without faultlines.
As someone who did a stint in this kind of construction: not possible, you'd still need to re-pave about 30-50cm worth of road, because curbstones are (usually) suspended in a bunch of concrete to avoid them getting dislocated by cars hitting or driving over them. The result will be a faultline from which you will get potholes in freeze cycles.
The proper way is to do everything at once, leaving one slab of contiguous asphalt without faultlines.