Why can't school buses use ICC?

Listen to the second speaker in this video.  This video was made by SEIU after local SEIU members went to Annapolis to lobby on education issues.  
The SEIU speaker in this video says that MCPS school buses aren't allowed to use the Intercounty Connector (ICC).  He goes on to say that it would save a lot of wear and tear and gas if school buses were allowed to use the ICC.
Why aren't MCPS school buses allowed to use the ICC? The issue can't be about money because the Montgomery County Council is about to approve a push to spend $5,000 - $8,000 per school bus to install outside cameras, and that will replace the $500 a piece outside cameras that MCPS has already purchased for school buses.