Tempe bus drivers voted Saturday to strike, less than 24 hours after the same move by bus drivers in Phoenix.

Veolia Transportation Services, which employs the union drivers, plans to bring in substitute drivers from across the country to handle the bus strike that began at midnight Saturday.

Veolia wants to have enough drivers on hand before the nation's sixth-largest city returns to work Monday, spokeswoman Valerie Michael said Saturday.

Amalgamated Transit Union Local 1433, which represents about 640 Phoenix bus drivers and 310 Tempe drivers, launched the strike outside several transit sites and bus garages after talks with Veolia last week failed to end a nearly two-year battle over wage and benefit terms.

Earlier Saturday, company officials said they are "shocked and disappointed" over the Phoenix strike, which resulted in 24 percent of the Veolia buses making scheduled runs.

Phoenix Mayor Greg Stanton scolded ATU and Veolia on Saturday for making residents the "innocent victims" for failing to reach a solution.

"I fully expect that they will stop the quarreling, get a grasp on the big picture and resolve this issue so our city's residents can continue to live their lives," Stanton said.

Local residents who rely on public transportation said Saturday they'll be closely watching what happens.

Arizona State University freshman Adrian Carlos, 19, frequently travels the Light Rail between Phoenix and Tempe and thinks more stops should be added, if the strike continues.

"It's pretty crowded right now. I usually have to stand up on most of the rides," he said.

Richard Giguere, 56, also regularly rides the Light Rail and doesn't know what more could be done if ridership goes up as a result of the strike.

"They are already running every 15 minutes now," he said. "It's really popular."

Without word as to when union members will fill their shifts, Veolia decided to pull in other drivers, Michael said.

"We're tying up all of our time trying to get service back up on the road and we would hope that the union show a sign of good faith and call-off the strike . . . and get back to the (negotiating) table," she added.

Michael said the 22-month dispute is likely the longest Veolia has ever had with one of its unions. One of the reasons, she said, is due to the 56 contractual items that were up for negotiation.

Six of the 56 items now remain in limbo and are the premise of ATU's strike, Michael said.

In negotiating those last items, Veolia offered a 401k retirement plan, healthcare coverage, five weeks paid vacation, 11 paid holidays and the ability to accrue 60 sick days and as well as five consecutive years of wage increases.

For information on active bus routes, visit www.valleymetro.org or call 602-253-5000.

The Associated Press and Republic reporters Lynh Bui and Eugene Scott contributed to this article.