WHILE IT'S MUCH too early to assess the collective strengths of the cabinet that Virginia Gov.-elect Gerald L. Baliles is assembling, his selection of Vivian E. Watts for secretary of transportation and public safety recognizes a highly respected public servant with a keen appreciation of state and regional concerns. In four years as a member of the House of Delegates, Mrs. Watts, Democrat from Annandale, has impressed colleagues on both sides of the aisle as a hard-working, informed legislator who is quick to grasp the political chemistry in Richmond. These are essential talents for the job she will assume, because transportation and public safety policy are sure to rank with education as the state's top policy fields in the Baliles years.

In each of these areas, Northern Virginia has vital interests that Mrs. Watts understands firsthand. Her home county of Fairfax, like its immediate neighbors, will be looking to Richmond for urgent help in relieving terrible traffic congestion. They're talking roads as well as mass transit -- neither one cheap, neither one by itself a sufficient response. That's not been music to the ears of rural legislators in the past, and nobody expects them to start singing the praises of subways when the General Assembly convenes next month.

Similarly, the subject of public safety has been touchy in Virginia, where a troubled corrections system has seen five directors in the past four years. But here, too, Mrs. Watts has kept informed without being linked to any single faction in the correctional policy debates that Virginia and so many other states have experienced.

As if these large missions weren't enough, the secretary also oversees motor vehicles, the state police, parole, alcoholic beverage control, aviation and military affairs agencies. But it is this broad scope of challenges that led Mrs. Watts to disrupt her hopes of serving 20 years in the legislature. It was a "very wrenching" decision, she says, noting that "I would not have been tempted by any other position within the Cabinet." If preparation is any key to success in her new role, Mrs. Watts should do a good job.