DENVER – A Colorado proposal to expand snow-tire requirements during winter months has hit a skid in the state Senate.

The bill would have required motorists without four-wheel drive to use snow tires or carry chains or cables during winter months on Interstate 70.

The proposal had the backing of Colorado’s ski industry, which said motorists using improper tires cause accidents that lead to costly traffic snarls. Commercial truckers also support the chain requirement, which already applies to them.

But a skeptical Republican used a legislative maneuver Friday to change the bill in a way that could doom it.

Sen. Randy Baumgardner revised the bill so it would apply on any state highway that goes over a mountain pass, an amendment that passed by a single vote because one expansion opponent was away from his desk.

Some lawmakers who support the snow-tire plan for I-70 don’t support it for smaller roads. The expanded snow-tire bill now faces almost certain defeat on its final vote next week.

Sen. Larry Crowder, an Alamosa Republican, said he’d vote against the expanded measure.

“In order to basically kill the bill, they’ve tied the entire state,” said Crowder, who supported the plan when it applied only to I-70 but was away from his desk when the expansion amendment passed.

Baumgardner said he wasn’t trying to poison the bill; he was trying to make it more equitable. The Republican from Hot Sulphur Springs represents a district with the most ski areas, including some far from the interstate.

“Why are we just concerned about the I-70 corridor?” Baumgardner said after the vote. “Why aren’t we concerned about those other towns and counties?”

His amendment would cover many mountain passes off the interstate, some of them close to ski resorts, including Monarch Pass near Monarch Mountain, Berthoud Pass near Winter Park Resort and Rabbit Ears Pass near Steamboat Ski Resort.

The sponsor of the bill, Sen. Nancy Todd, said she’d appeal to her fellow senators to reverse the expansion and save the effort.

“This bill is about I-70 because it is the major congestion, and it is where traffic is stopped,” said Todd, D-Aurora. “And it’s altering our tourism.”

On the Net

House Bill 1173: http://bit.ly/1y9dqZo.