ST. PAUL — On more of Minnesota’s two-lane state highways, motorists could soon be free to drive above 55 — legally.

As part of an expansive budget bill signed into law last week, state lawmakers nudged transportation officials to boost the speed limit to 60 miles per hour on lane miles where it can “reasonably and safely” be done. By 2019, traffic engineers must examine every mile of road with a 55 mph limit and determine if it is prudent to go higher.

It’s an enormous undertaking. There are 6,771 miles on two-lane/two-way state highways now covered by a 55 mph limit. Officials figure they’ll get through about one-fifth per year, starting as soon as next month. They will analyze each stretch’s crash history, design, lane width, sight lines and ditch slope.

“The fact we’re studying the roads does not mean you can jump to the conclusion that all roads will be raised to 60 miles per hour,” said Peter Buchen, assistant state traffic engineer at the Minnesota Department of Transportation.

But the agency has been moving in that direction. In 2005, the department bumped the limit to 60 mph on 791 miles of two-lane highways and added another 750 miles last year. Buchen said those were prime candidates — straight, wide-open stretches with clear sight lines and low incidence of crashes. He said limits on hillier, curvier highways probably won’t budge.