Hundreds of thousands of Denver-area commuters faced the prospect of carpooling, biking or walking to work Monday after transit workers voted to strike for the first time in 24 years.

About 200 bus drivers, mechanics and light rail operators for the Regional Transportation District hit the picket lines early Monday, dispersing to bus stops and light rail stations around the metropolitan area, said Todd Platten, an executive board member of the Amalgamated Transit Union Local 1001.

Stikers walked back and forth on the street in small groups, bundled up on the cold spring morning, and held signs that read: "RTD put us on the street, but we'd rather be serving you" and "RTD not fair."

Officials said it would run 45 percent of its bus routes, but rail service, regional service, transit centers, and the 16th Street Mall in downtown Denver would be shut down.

"Our members have been working seven days a week without a day off and have worked for three years without a wage increase," said Local 1001 president Yvette Salazar. "We want to apologize to our riders, but the workers are extremely tired. This is the last straw."

The strike hampered bus and train service for a system that had 86.2 million passenger boardings last year — averaging about 275,000 per weekday — as well as fans expected to pack Coors Field for the Colorado Rockies' first day of the baseball season.

Carol Erven-Robinson, 25, said she'll have to find another mode of transportation from a halfway house where she is staying to a downtown restaurant where she works.

"There are 160 women here and all of us rely on the bus system to get to work, to get to appointments, to get anywhere," said, Erven-Robinson. "We're all trying to figure out how do we get to work."

Fifty-five percent of the 1,750 Amalgamated Transit Union Local 1001 members voted Sunday to reject the Regional Transportation District's latest contract offer, union officials said.

"I kind of felt like this was going to happen. I feel kind of numb," said bus operator Deb Sena. "But do they want the best people for the job? Or do they just want any person off the street?"

The rejected offer would have shared any increases in health insurance premiums 50-50 between workers and the agency in the last two years of the contract. The proposal also included raises of up to $1.80 an hour over three years, made up of quarterly raises of 15 cents an hour. A one-time $250 bonus was also offered.

"It's very disappointing," said transit spokesman Scott Reed. "We had the largest wage rate increase offer in RTD's history on the table, and we agreed to do exactly what the union requested, which was split possible future health care cost increases."

In Boulder, the University of Colorado made preparations for the estimated 10,000 students, faculty and staff who use the transit system, urging them to carpool and walk or bike to campus. The school also opened some of its parking lots for free.

Salazar said workers would remain on strike until a better contract is offered. The local's executive board recommended its members approve the offer; union members overwhelmingly rejected a previous offer on March 26.