A tangled web of state laws could make it more difficult to test self-driving cars soon, representatives from automotive companies told a congressional committee Tuesday.

Spokespeople from automakers such as General Motors, Toyota, and Volvo, and representatives from ride-sharing company Lyft and a leading think tank told a House committee that granting exemptions for self-driving cars to test on public roadways could help automakers and tech firms speed development.

“Everyone should have (self-driving cars) available to them," Lyft Vice President for Government Relations Joseph Okpaku told House Representatives.

According to testimony from a subcommittee of the House Energy and Commerce Committee, more than 50 bills are winding their way through state legislatures regarding self-driving cars, and although they haven't yet hampered development or testing, automakers say that they could soon.

Specifically, automakers are looking for relief from a Department of Transportation mandate that test vehicles meet minimum safety standards. Many of those standards include driver controls that automakers and ride-sharing services say are redundant and could add costs to development.

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Anders Karrberg, a Volvo vice president for governmental affairs, said his company was preparing a full-size Volvo XC90 to be SAE Level 4 compliant by 2021. That would mean that the SUV could operate independently, without driver input or attention, on certain roadways in certain conditions.

Testing those cars could be difficult without a formalized waiver process from federal agencies that could allow Volvo to test that technology, regardless of state.

Automotive representatives told the committee that the technology could save thousands of lives if implemented, but added that the sensors and software could add tens of thousands of dollars to the cars and would likely be initially reserved for fleet or ride-sharing services that could amortize the costs of those in their cars.

In September, the NHTSA issued preliminary guidelines for autonomous vehicles, but setting conditions for a waiver program to forgo some current mandates hasn't yet been finalized. House Representatives considered allowing some rules to be relaxed for certain conditions—i.e. whether the self-driving cars would be used on public roadways or on closed roads—while others would stay in place.