The 1986 session of the Virginia General Assembly, which begins today, has plenty of important business to do during its 60-day run -- starting and ending with adoption of a budget for the next two fiscal years that will be in the range of $18 billion. Top considerations this year -- for the state in general and Northern Virginia in particular -- are likely to be education and transportation.

Of special interest to Northern Virginia is a pledge by outgoing Gov. Charles Robb, concurred in by Gov.- elect Gerald L. Baliles, to increase spending for public school education by several hundred million dollars -- or enough to finance fully Virginia's Educational Standards of Quality, plus increases in teachers' salaries and in other educational programs.

The transportation picture so far looks good for Northern Virginia. Legislators from this area are pleased by the appointment of Northern Virginia Del. Vivian Watts as secretary of transportation and public safety, as well as by the replacement of old-line Harold King as commissioner of highways and transportation by Ray Pethtel, who as head of the legislature's Joint Legislative Audit and Review Commission has conducted several studies critical of department policy.

Northern Virginia's legislators will seek $4 million in state funds, to be matched by state and local money, to start a two-year trial of commuter trains serving the Manassas area of Prince William County, Fredericksburg and portions of Fairfax. Most local legislators also are likely to support a bill increasing gasoline and other taxes slightly and trimming the exemption for gasohol, to produce $100 million in increased financing for much-needed road construction projects across the state.

We also will be alert to fend off possible renewed efforts by a coalition of rural and western senators to strike the state's annual $21 million contribution to Metro. To help justify Virginia's aid for Metro, Northern Virginia businesses financed a study of the benefits to all of the Commonwealth from construction of the Metrorail system in Northern Virginia. This study reveals that the state's contributions have proven a valuable investment -- generating in the current fiscal year not only transportation benefits for this area but also more than $2 for every state dollar invested.

Two other transportation matters: we will be watching out for renewed efforts by the trucking lobby to secure access to most state roads for wider and longer trucks. Also, during last year's session the House of Delegates passed a mandatory seat belt law that then was defeated in a senate committee. A similar bill certainly will be introduced this year, and it should have better prospects for enactment.

Virginians can expect another effort to enact a state lottery law -- a proposal defeated in the past by church opposition, despite Virginia's history of using lotteries until about 1820 to support education.

In the environmental field, Baliles has pledged a better focus by creating the office of secretary of natural resources. Virginia will again appropriate more than $20 million during the next two years to continue cleaning up the Chesapeake Bay; and a state study will seek a fair solution to the controversial problem of how to make water resources available from areas of abundance to water-short areas such as southeast Virginia.

As for public health and safety concerns, a study of the increasing impact of Alzheimer's disease on many older Virginians and their families should lead to matching money to establish five regional respite centers for victims. And Virginia's Victims of Crime Compensation Act is likely to be made more generous and responsive.

There's an important constitutional change pending too: to allow the governor, beginning in 1989, to succeed himself for one additional four-year term. This passed the General Assembly last year and must pass again before it can go to the voters by referendum.