Anish we have some suggestions on how to enforce this in the Operations & Maintenance section of the Checklists tab, above. These are distilled from quite a bit of project experience.
Karen, I agree with your thought regarding the dedicated carpool drop-off lane. Shouldn't the intent of the credit be voided for carpool drop-off if the project is demstrated at least 80% of the school boundaries are within walking distance? The intent of this credit would be to encourage low-emitting vehicle drivers for FTE.
Hi Lindsey: Nice to hear from someone so experienced with LEED-S projects! We did consider limiting the parent drop-off lane to carpools (fuel-efficient or not), but the last thing any Principal wants is to have her staff confronting angry parents who feel it is their "right" to let their only child have an extra 1/2 hour sleep and then drive them to the door. To be fair, carpooling and walking are hard on working parents, who don't have the time to walk with children, then go back to work. My kids were able to walk to school by themselves, but that was years ago and the culture has changed. I wish USGBC would share good ideas--I bet there is a LEED school that came up with a great alternative transportation plan and got ID credit for it!