IN WHAT turned out to be a legislative field day for Virginia Rep. Frank Wolf, local commuters won important congressional approvals Tuesday for safer, swifter travel on the roads and rails of the region. The House transportation subcommittee has blessed a fine package of proposals backed by Mr. Wolf, which includes money for more Metro construction, for additional car pool lanes on I-66, for a number of projects to improve truck safety on the Capital Beltway and other area highways and for improvements to the Baltimore-Washington Parkway. These projects are important not only to relieve pressures on rush-hour travelers locally but also as examples of public safety measures that could benefit other areas across the country.

Mr. Wolf teamed up with Maryland Rep. Steny Hoyer to win support for the Metro and highway provisions, which now go to the full Appropriations Committee. Money for the I-66 lanes would be designated a "demonstration project," which would permit spending without a separate congressional authorization. That's speed of the sort not found on the rush-hour lanes now in place and would make a large, welcome difference, especially to residents of western Fairfax County and Loudoun County.

The moves for a safer Capital Beltway are part of a continuing Wolf-Hoyer effort that began in the wake of a series of terrible accidents two years ago. Mr. Wolf convened a meeting with the Federal Highway Administration to examine and effect changes in truck traffic. Better signs, lane restrictions and unmanned radar were among the first results. Provisions in the latest bill would explore combining traffic violation stops of trucks with safety inspections. Experiments also would begin on truck-activated traffic signs that could warn drivers of the potential for rollover on certain ramps and aid would be available to start new commercial motor vehicle safety programs administered by the various local governments.

None of this will relieve the volume of traffic on the roads or guarantee on-time arrivals for commuters. Additional lanes, safety measures and new and better Metro service can't make commuters disappear. New roads -- including outer bypass routes around Washington -- must be built. But the new measures surely will help.