The Jefferson County Board of Education will consider proposed revisions to the district's student assignment plan when the panel meets this evening.Superintendent Sheldon Berman wants to delay the implementation of most of the new assignmment plan for middle and high schools by one year, until 2011-2012.Berman says he wants the postponement to deal with transportation problems that have plagued the new assignment plan for elementary schools which began this year. It has resulted in lengthy bus trips for some students each day.He also wants to make some transportation changes to the elementary plan, including a 75 minute cap on the time any youngster spends on a bus.The board will meet at 7:00 this evening. The board normally meets on Mondays but yesterday's meeting was postponed because of the Yom Kippur holiday.The school system was required to formulate new assignment plans following a U.S. Supreme Court ruling in 2007.