When using PRI, GLARE would be next to impossible because the CO switch and the CPE "communicate" over the DCH before a channel is selected. So during call set up the two "agree" on what BCH is selected.
One purpose of GROUND-START lines/trunks was to reduce or eliminate the GLARE problem, which it did in elctromechanical systems, but sort of came back when electronic and microprocessor controled PBXs showed up on the scene. That was primarily because of timing issues in the software. So the low-to-high and the high-to-low options were added to compensate. Most of this applies to the "LINE" side of the CO switch.
On the "TRUNK" side, there are different "hunting" options available. As Tim has mentioned some of those are available for both types, but the LECs don't always make all those choices known or available to subscribers.
I like the round robin hunting format for outgoing calls because all the trunks get a chance of being used and is easier to spot a bad one.
....JIM....